-- ADVENT Captains --

Captains and Troopers make up the bulk of the early and mid game. They got the most variants from this mod for that reason. The Captain is supposed to be the most impactful unit in its pod and set the basic tone for the encounter. Unlike most ADVENT, which come in two or three tiers, Captains have a fourth tier, the ‘Exalted Captain’. These will only appear near the end of the game.

Sniper
Until XCOM started its’ operations, ADVENT didn't have a need for dedicated snipers. Now that there's a hidden war between the aliens and the resistance, the appearance of long-range units is a logical consequence. Lending fire support to expendable Troopers, the Sniper Captain commands his squad from the back of the engagement.

Beastmaster
A pariah even among his fellow ADVENT clones, the Beastmaster is the result of splicing Chryssalid genes into the ADVENT sequence. Beastmasters are able to rudimentally communicate and connect with Chryssalid workers that have been isolated from their nest. Another experiment that has been deemed a failure for widespread use, the last few of them are now getting deployed against XCOM.

Riot Control
Although the deployment of Stunlancers during the early days of the ADVENT administration was able to suppress most protests and riots, some still popped up. ADVENT started sending the Riot Control officers and Anti-Riot MECs to deal with those in non-lethal ways. Today, these units are still in use against XCOM as a support for the more traditional ground troops. Their Flashbangs and Stun Batons are capable of subduing enemy targets. Experienced Riot Controls carry midrange tasers to disable enemies which are then captured and shipped to the nearest Blacksite for questioning and "processing".

Adept
ADVENT and the alien force behind them were always interested in creating psionically active troops. While the Adept was deemed a failed experiment and unfit for mass production, a few of them showed enough promise to be integrated into the ADVENT war machinery. Typically, Adepts are capable of limited mind-altering powers, but rumors exist of Advent Captains that influence multiple targets at once or even use a Teleport ability to position themselves on the battlefield.

Kommissar
Kommissars are a remnant from the early days of ADVENT, when it was still using non-Alien, human soldiers. The Kommissar's duty was making sure that morale in the ranks was always high by making those with questionable devotion to the ADVENT cause disappear. Today internal security is no longer a concern and the Kommissar has been outfitted with heavy armor and moved to the frontlines, where his heavy revolver sidearm is now pointed at enemy soldiers.

General
ADVENT captains are trained directly on the frontlines. Generals are experienced captains that lead a squad of lesser captains to gain experience on the battlefield.

-- ADVENT Troopers --

If Captains set the general tone for an encounter, then Troopers are there to provide the nuances to this challenge. Individually, their variants offer much less of an impact than the Captains do, but since there’s usually multiple troopers in a pod, the little advantages pile up fast.
Variant troopers wear one of 6 different armor patterns: there’s armor suits with grey parts and armors with dark red parts. For each of those two, 3 variations exist. Troopers with a defensive or utility role have increasing amounts of grey on their armor. Troopers that focus on offense wear red.

Heavy
ADVENT Troopers that show exceptional performance on duty are often promoted to Heavy. This gives them the privilege of getting to use better armored vests. Apparently, ADVENTs supply of higher tier armor seems to lag behind the sheer numbers of troops they produce, or else this Heavy would probably be the standard.

Gunslinger
Gunslingers use light pistols that are cheap to produce in large quantities. While the weapons are of shoddy quality and unlikely to inflict critical wounds, the Gunslinger is still able to use them to spread minor lacerations and flesh wounds among opponents. Caution is needed when facing experienced Gunslingers, they have been seen using a heavy revolver similar to the one carried by Kommissars.

Demolitionist
Specialists in blowing stuff up, the Demolitionist can wreak havoc on the enemy and the surrounding area with his heavy payload. Depending on the urgency of the situation and on how subtle ADVENT thinks it needs to be, Demolitionists can come with everything from basic frag grenades to wrist-mounted rocket launchers.

Sentinel
Sentinels fulfill two roles in the ADVENT lineup. While out of combat, Sentinels are the designated scouts, able to pick up anything suspicious from afar. During combat, they will use their training to anticipate enemy movement and answer to it with reaction fire.
 
Wrecker
The development of heavy combat armor by the resistance forced ADVENT to deploy these anti-armor units. Wreckers use high-tech ammunition that can pierce armor and then shred it from inside, causing permanent damage to the equipment and the person it is meant to protect. Naturally, stray shots with these rounds also cause devastating damage to the surrounding area.

Revenant
A failed attempt at creating suitable hostbodies for the Elder, the Revenant are ADVENT Troopers with latent psionic tendencies. They aren't able to use psi abilities of their own, but they are able to 'store' Psi Energy, in this case the energy used by Sectoids to raise fallen troops to fight again. Revenants are troopers that on death raise again as Puppets. Lately, ADVENT also started hiding Faceless among Troopers. While these 'Shoggoths' are technically a different alien species, XCOM started classifying all Troopers with hidden identity as 'Revenant'.

Striker
In close quarters, few opponents are more dangerous than ADVENT Strikers. They combine high mobility and the damage output of Shotguns to flank enemies and take them out with one or two wellplaced shots. Their close combat training enable them to take shots of opportunity at any enemies close to them. High ranked Strikers do get sizeable bonuses to Aim and Critical Chance at flanked targets.

Gatling Trooper
The latest response to the escalating arms race between aliens and resistance, the Gatling Troopers are armed with heavy cannons similar to the armament of the ADVENT MEC. They are able to either use the cannon to plow through cover or to spew a truly exceptional number of bullets at the enemy.

-- Other ADVENT forces --

Besides Troopers and Captains, ADVENT also has some special purpose units at its disposal. A Better ADVENT adds a few additional variants for them as well.

- Shieldbearer -
Shieldbearers fulfill their intended purpose really well already, so their variants focus on different loadouts and abilities that come with it.

Breacher
The offense oriented variation of the Shieldbearer. Breachers carry a shotgun and have increased mobility.

Guardian
Guardians are defensive Shieldbearers that are armed with a Sniper Rifle. They have reduced mobility, but a slight aim bonus.

Tech Commando
Just like XCOM's Specialists, the Tech Commando fields a Gremlin drone into battle that he can use in multiple ways. With Detonation Protocol, the Gremlin is sent at an enemy target to detonate one of the explosives carried by the target. Shield Protocol applies a single target energy shield that protects against large amounts of damage to a friendly target. Tech Commandos do not carry the standard issue shield module that other Shieldbearers use.


- Stunlancers -
Lancers appear in high numbers throughout the campaign. A Better ADVENT changes their AI behavior considerably, turning them from a suicidal melee unit into a close quarters unit switching freely between their gun and their stun baton.

Assault
For a unit with such a focus on close combat as the Stunlancer, it was only logical for ADVENT to start outfitting them with Shotguns for increased firepower at the preferred engagment range.

Shieldlancer
By adding shield modules to the loadout of Stunlancers, ADVENT created an efficient hybrid unit that will throw down a shield for all friendly units and then charge into close quarters.

Trauma Lancer
Inspired by the surprising success of the Stunlancers in real combat situations, ADVENT have been looking for another way of subdueing enemies without necessarily killing them. As a result, Stunlancers have been deployed that don't rely on the iconic Stunlance anymore, but instead bring Taser pistols that can inflict similar effects without the need of getting in close range. They do less damage than the Stunlance does, but the secondary effects are just as potent.


- MECs -
Due to their heavy armor and the capability to be carry a lot of equipment without being hindered, ADVENT started using MECs for more than just mobile artillery.

AutoDoc
While generally ADVENT doesn't really care about the life of single Troopers, they did realize that a medical unit will increase the overall effectiveness of all units around it. By adding a medical Gremlin to a MEC chassis, they created a unit that can offer instant medical care while still adding some firepower to the field. AutoDocs don't carry an artillery module, but they do have the oversized cannon that is issued to all MECs.

Hazard MEC
The Hazard MEC is a specialized artillery unit that focuses on area denial. By coating large areas in acid, ADVENT uses these MECs to turn large patches of terrain into slag and drive out any resistance members that would want to hide in there. ADVENT will deploy this unit only when getting desperate, as it is obviously a PR nightmare for them. Hazard MECs are basically a walking war crime.

Anti-Riot MEC
One of the first MEC units to be deployed by ADVENT, the Anti-Riots were a common sight when the aliens still had to supress civilian unrest. These old units have only lately been dusted off again to be used against XCOM. They are equipped with a multi-purpose launcher that can fire either Smoke Grenades to provide cover for allies or a Cluster Flashbang that can impair enemies in a wide radius.

- Drones -
Small and agile units that are used by ADVENT to provide some support in scout squads. Unlike Gremlins which depends on a controller, they have been outfitted with a rudimentary AI. Drones are mostly used as scouts, but they are also equipped with a miniature laser and a stun prod which they can use to lend some fire support.

-- Sectoids --

In vanilla XCOM, Sectoids are often not as relevant as they should be, considering their status as being pretty much the face of the alien force. The variants introduced by Better ADVENT use a much improved AI alongside their new set of abilities.

Negator
An odd variation of the Sectoid, the Negators' presence cancels out any mind-altering effects around him. Originally deployed to combat XCOM's recent development at creating Psi Operatives, Negators have also been useful at mitigating the use of Flashbangs, Tasers and similar equipment.

Soldier
Some Sectoids show only faint traces of psi activity. Those are put through extensive combat training and used as fodder for the frontlines. They are as aggressive as rabid dogs, their only goal is taking an enemy down with them.

Mindbender
The opposite of a soldier, the Mindbender shows an above average aptitude for psi powers. Their Mindspin can break the will of all but the strongest soldiers.

Captain
If a Sectoid Soldier survives long enough against all odds, he is assigned a squad of young soldiers and acts as their superior, coordinating them in battle. These 'Plasma Squads' are extremely dangerous due to their reckless tactics.

Puppeteer
Some Mindbenders have a knack for the control of Psi Zombies, disregarding the use of other psi abilities in favor of what XCOM colloquially dubs 'Puppeteering': The constant resupply of the frontlines with the raised bodies of the fallen.

-- Vipers --
Vipers have a diverse set of abilities. They are in a good spot in terms of design and balancing – the only variants needed are a few that highlight some of those abilities.

Adder
The Adder is an advanced version of the Viper. Adders share most of the Viper's characteristics, but they have increased stats and use Chain Shot in combat.

Wyvern
Wyverns are a variant that focuses on spreading area damage with their spit weapon. Unlike vanilla Vipers, Wyverns spit globs of fiery napalm that causes the target area to burn for several turns. They are able to do this every other turn. The fire spit does no damage on impact, but sets everyone on fire. Wyverns don’t have the tongue grab ability that regular Vipers have.

Boa
Boas are heavy melee units that start appearing late in the campaign. They use their tongue and their Bind ability whenever they are able, even on reveal. They have a large amount of health and armor. They will only lose their grip on whoever they are binding after being dealt a considerable amount of damage. Their damage on Bind and per turn is increased, but they can’t dodge and are unlikely to use cover.

Mamba
A very efficient alien sniper unit that wields a Boltcaster. They have tremendous aim, even over long distances. To make matters worse, they can pick off wounded soldiers with inhuman precision.

-- Mutons --

The Muton is a basic alien grunt. In vanilla, the Advent troopers fill most of the niches that Mutons should have. ABA turns Mutons into the terrifying soldiers they should've been in the first place..

Muton Pyro
Pyros use incendiary Dragon Rounds that inflict Burning on any targets hit. They are tougher than regular Mutons and their special ammunition ensures that even marginal hits cause life-threatening damage.

Muton Infector
Infectors load their rifles with poisonous Viper rounds. Like Pyros, they are tougher than regular Mutons. Their poison ammo impairs enemies while constantly draining away their health.

Muton Captain
The Muton Captain can bolster the combat readiness of surrounding allies with a Warcry. Their ability to fire multiple shots in a short timeframe lets them cause a lot of damage.

Muton Champion
For a Muton, the Champion is surprisingly defensive. They carry personal shield generators and can react to being shot with a variety of countermeasures to mitigate further damage. Like Captains, they use a Warcry.


-- Berserkers --

The vanilla game allows Berserkers to only appear only in Terror missions. A Better ADVENT removes that limitation and lets them loose on all missions.

Firestarter
A variation of the Berserker, born from the same experiments that created the Wyvern, this hulking monster will utterly dominate any close combat situation. Not only does it possess the melee abilities and toughness of the Berserker, it also can spit fire like an mythical dragon. Their firebreath can torch everything in front of them in a short, but wide cone of effect.

-- Codices --

Codices are a very cool and unique midgame unit that sadly loses a lot of its bite towards the endgame. Due to their innate defensive abilities (dodge and cloning) they will often not run to cover on reveal and will instead go straight for their powers.

ICE
The Intrusion Countermeasure ("ICE") is specialized on taking down key opponents. They are equipped with a Boltcaster and make heavy use of their Teleporting ability to line up precision shots.

Bomber
Tanky and focused on disabling enemy weapons, the Bomber lends fire support to squads of combat units by repeatedly firing of Psi Bombs.

Codex Splitter
Splitters do not have followers, they roam completely on their own. Instead of relying on other units for support, they start rapidly chain-splitting into multiples as soon as they are engaged. On top of that, each copy regenerates 2 points of health every turn, which will enable to split again on the following turn.

ADVENT Codex
When ADVENT needs to respond to emergencies in a fast manner that doesn't allow for an airdrop, ADVENT Codices can teleport whole squads of Troopers directly onto the battlefield. The Codex takes the place of the Captain in that situation, holomarking targets with their rifle.

Codex Nullifier
The Nullifier uses Stasis to lock down the highest ranked soldier in sight. Like other Codex variants, they use this ability on reveal.

-- Archon --
The Archon is a case of an enemy that has a unique set of abilities and is already non-trivial in vanilla XCOM2. Archon variants pick one aspect of their ability set and improve on it. Their high defense makes them ideal units for ability use on reveal because they don’t need to run for cover.

Torcher
Archon Torchers will use Devastate, a high impact version of Blazing Pinions immediately on reveal if they can find a good spot for it. For that reason, engaging a pod with a Torcher at a bad time can be very dangerous. Devastate has the capability to stun or even knock targets unconscious.

Executioner
These are the melee version of the Archon, unable to use Blazing Pinions or plasma shots. They are very tanky thanks to a higher dodge chance and regenerating 2 life per turn. On top of that, they have a special version of the Archon staff that drains the life out of enemies and gives it to the Archon.

Sentinel
Like the Sentinel Trooper, the Archon Sentinel is a unit focused around Overwatch abilities. It uses Guardian and Covering Fire, which form a deadly combination with its high defense. In addition, they immediately enter Overwatch on reveal.

-- Andromedon --
With their unique appearance and abilities, these are already a force to be reckoned with.

Prometheus Suit
This is a firebased unit that can torch whole areas and cover them in flames. Their fire attack doesn’t cause any impact damage, but it will generously spread the burning status among XCOM soldiers.

-- Gatekeeper --
Gatekeepers are dangerous endgame units whose high powerlevel doesn’t need further improvement. Vanilla Gatekeepers switch between opened and closed state and use different skills in each state. The two variants each specialize in one of those states.

Gatecaller
The Gatecaller spends most of its time with an open shell. This gives it quick access to the Mass Reanimation ability, enabling it even to cast it on reveal. When no good targets for reanimation are around, Gatecallers will often use their tentacles in melee to drain the life out of soldiers.

Doomsphere
The Doomsphere lacks any psi abilities and instead acts as a heavy weapons platform. Relying on its heavy armor, it will try to flank enemies and evaporate them with its heavy laser.

-- Chryssalids --

A Better ADVENT adds Chryssalids back into regular missions. Also, they now come in a variety of tiers and versions. A Chryssalid pod always has one leader unit that comes with a couple of generic melee bugs. As Chryssalids grow in size, they become tougher and more combat ready, but also less agile.

Crawler
The smallest Chryssalids aren’t poisonous, have only little life, do puny damage and have no armor. They have a lot of mobility, but that shouldn’t stop even rookie XCOM soldiers from squishing them.

Drone
Drones are still a bit weaker than the vanilla Chryssalid. They are poisonous and have one point of armor. They have moderate health and damage.

Hunter
Hunters are slightly stronger that the vanilla Chryssalid. Like Drones, they are poisonous. Two points of armor, a good amount of health and respectable damage make them a credible threat.

Hunterkiller
Hunterkillers are the endgame variant of the common Chryssalid. They have 3 points of armor. Health and damage are improved even further. Obviously they are poisonous.

Spitter
Chryssalid Spitters are a low ranked hunter unit. They can spit a poisonous projectile with pinpoint accuracy that causes immediate health risks for the affected target. Spitters sometimes lead small groups of Crawlers or Drones on hunts. A Spitter can both spit and attack in one turn.

Bleeder
The Bleeder constantly leaves acid pools wherever he passes, blocking terrain and destroying the surroundings. Chryssalid Bleeders are Drones, genetically modified to constantly secrete an acidic substance that causes harm to the surrounding environment and every organic being that touches it.

King
The most physically imposing members of the Hunterkiller caste are chosen by the Chryssalid Queen as their personal mates. A nest will often have multiple Kings vying for the Queens affection, making them ferocious and eager to prove themselves by fearlessly engaging anything that would threaten the hive. Being closely linked with the Queen grants them an immunity to mind altering effects of all kind.

Abomination
Abominations don't seem to serve a regular purpose in the nest, apparently they are an aberration caused by unchecked growth due to defective genetics. Most of these collapse under their own weight, but the few that survive are truely monstrous enemies that can devastate whole countrysites before finally being put down.

Queen
The heart of the swarm. The Queens' primary purpose is constantly creating more members for the hive. While this usually takes some time, they can throw the underdeveloped Chryssalid spawns into battle when coming under fire themselves, thus creating an impromptu Chryssalid army of considerably size. This works similar to a more limited Prime reaction ability. Chryssalid Queens aren't psionically active, but the latent psi abilities that let them control the hive also make them immune to all forms of psi influence.

-- Spotters --
Spotters are enemies that roam on their own and call for backup on reveal. A successful ambush can stop the distress call from ever happening, but if they survive it, the damage will be done. There are several possible reinforcement pods. Most of these pods will arrive on the next alien turn, but some of them may arrive instantly or only two or even three turns in. The longer it takes, the more powerful that incoming pod is going to be. Spotters have better stats than their vanilla unit, slightly higher sight and detection ranges and also some defense/dodge to make up for not running into cover on reveal.

Sectoid Spotter
They can only request weak reinforcement pods from the alien base. Example pods: A Puppeteer with 2 Puppets. 4 Chryssalid Crawlers. A single Berserker.

Viper Spotter
They can call for more advanced reinforcements. Example pods: 2 Wyverns and a Viper. A Sectoid Negator, Mindbender and Soldier. A Muton Pyro with a Berserker and vanilla Muton.

Muton Spotter
Muton Spotters are the final tier of spotters and call down the scariest pods. Example pods: 8 Chryssalid Crawlers. 2 Firestarters and a Berserker. An Archon Sentinel, Executioner and Torcher.

-- Prime Units --

Prime Units are endgame versions of enemies, designed to spice up the endgame. They are considerably more dangerous than their vanilla counterparts. All Prime units have a reaction ability that acts as a very limited version of the ruler reaction system from the Alien Hunters DLC. This reaction ability will give them immediate bonus actions whenever they are dealt damage.

Sectoid Primes
These are more powerful versions of the Sectoid Negator, Captain, Commander, Puppeteer and Soldier. They have more life, armor, defense and an improved weapon.

Muton Primes
Muton Primes are a hybrid of the Muton Captain and Champion, using some of their abilities and have access to them with their reaction ability, too. They are equipped with a Beam Cannon and better armor, making them a very serious threat.

Berserker Primes
Berserker Primes are the first Prime units the player encounters. Their stat increases are moderate, but they will give the first taste of the Prime reaction system. This extra action isn’t restricted in any way, they can dash, punch or use a special action like Firebreath. Yes, that means there are Firestarter Primes, too.

Sectopod Prime
The pinnacle of ADVENT engineering, the Sectopod Prime is by far their heaviest combat unit. With armaments that can wipe out whole squads and a fully automated AI that can react to anything that would dare even scratch the paint on this hulking war machine, the Sectopod Prime is going to make a lasting impression. Prime Sectopods have a stealth circuit that hides them from the pre-mission scan of the Shadow Chamber.

The lack of images gives me a panic attack... There's a ton of stuff to be done :(

i am currently working on it, come back in an hour or so :)

I mean for the ones that I haven't done anything yet, like ALL the primes, spotters etc