I would also like to know a list of items and descriptions of what each one does

WARNING: DO NOT READ THIS POST, IF YOU WANT TO BE SURPRISED BY GRIMY's UPGRADES !

This here seems like the right place to post, I guess some people (myself included) have looked over and over for something like this. So if you are not in the mood to scroll through the localization file yourself (which is where I took all this info from), here it is:

PRIMARY WEAPON UPGRADES

Smart Tracker
Decrease Graze Chance by 10/20/30%.

Personal Scanner
Increase sight range and visibility by 1/2/3 tiles.

Red Dot Sight
Increase critical hit chance and aim against flanked targets by 5/10/15%.

Vital Point Targeter
Bsc adds Deadeye ability. Adv/Sup also grants +5/10% aim.

Heavy Frame
Increase damage by 20/25/30% and decrease mobility by 2.

Hangfire Propellant
Increase damage by 1/2/3 and decrease aim by 5/10/15%.

Suppressor
Increase aim and critical hit chance while not visible.(AKA Shadowstrike) by 15/20/25%

Heat Sink
Bsc adds Suppression ability, Adv also adds Demolition ability, Sup also grants 1 use of Killzone ability

Lightweight Frame
Increase mobility by 1/2/3 and decrease damage by 15/20/25%.

Recoil Stabilizer
1/2/3 charges of Run & Gun ability.

Progressive Trigger
1/2/3 charges of Rapid Fire ability.

High Cycle Chamber
+5/10/15% aim, +30/35/40% damage, crit chance -100%.

High Caliber Clip
Increase damage by 30/35/40% and decrease clip size by 2.

External Processor
Increase hacking and psi offense by 5/10/15%.

Wildcat Cartridge
Increase critical hit damage by 1/2/3.

Frontload Magazine
+10/15/20% aim and crit chance on first shot, but -10/15/20% for each shot after the first.

Reserve Magazine
Last shot from a magazine has +40/50/60% aim and 10/20/30% increased crit chance.

Ammo Synthesizer
Creates 1 ammo once per turn, loose ability to reload. Adv/Sup grants 20/40% chance to create 2 ammo.

Dragon Magazine
Gives and replaces any existing ammo with dragon rounds. -1/+0/+1 Clip Size.

Venom Magazine
Gives and replaces any existing ammo with venom rounds. -1/+0/+1 Clip Size.

Bluescreen Magazine
Gives and replaces any existing ammo with bluescreen rounds. -1/+0/+1 Clip Size.

Sentinel Scope
1/2/3 uses of sentinel overwatch.

Undertaker Sensor
Increases critical hit damage by 1 per visible enemy, up to 3/4/5.

Duelist's Stock
Increase damage by 25/30/35% when user can only see one enemy and that enemy can see the user.

Seigebreaker Scope
Increases aim and crit chance against overwatching enemies by 25/30/35%.

Squad Video Feed
Bsc adds Squadsight abilty, Adv also adds Long Watch ability, Sup also adds Ever Vigilant ability.

Double Tap Targeter
Bsc adds Chain Shot ability, Adv/Sup aslo add 1/2 uses of Hail Of Bullets.

Belt Feeder
Provides 1/2/3 uses of saturation fire.

Anti-Material Barrel
Increases shredding and armor piercing by 1/2/3.

Custom Stock
Increases damage by 1/2/3, regardless of hit or miss.

Twitch Trigger
Grants 1/2/3 uses of Serial ability.

Maximum Caliber Clip
Increases damage by 100% but decreases clip size to one. Adv also grants +3 Amor Piercing, Sup also grants +15%crit chance vs unflankable targets

SECONDARY & UTILITY UPGRADES

Sidearm Holster
Start your turns with an additional action point. Reduce mobility by 6/5/4.
Can be strapped to ALL utility & secondary weapons, including the Gremlin!

SECONDARY UPGRADES - PISTOLS

Widowmaker
Grants 1/2/3 charges of Faceoff ability

Lawbringer
Gives 1/2/3 charges of Fan Fire ability

Hand of Light
Lightning hands cooldown reduced to 1. Adv/sup also grants +5/10% Crit Chance.

Wolf's Tooth
Provides 40/50/60% chance of a free action points on kills. Adv/Sup also grnat +5/10% Crit Chance

Thunder and Lightning
Increase pistol damage by 1, sniper rifle damage by 80/90/100%, and lose the ability to reload.

SECONDARY UPGRADES - MELEE

Blade Flourish
10/20/30% increased dodge piercing.

Serrated Edge
+10/20/30% crit chance and +1 crit damage.

Lightweight Blade
+1/2/3 mobility

Vibroblade
+1/2/3 Armor Piercing

Momentum
+1 crit damage,+30/45/60% crit chance vs targtes farther than 10 tiles away.

Parrying Blade
Decrease melee damage taken by 4/5/6.

Dark Inquisition
Increase melee damage by 80/90/100% when concealed.

Long Crusade
Gain 2 armor per slash for 2/3/4 turns.

Big Game Hunter
+30/45/60% crit chance, +1 crit damage vs unflankable targets.

Broken Blade
+30/35/40% shotgun damage -30/35/40% sword damage

Death's Hand
+2 Reaper damage after every kill. Adv/Sup also grant +1/2 base damage

Razor's Edge
Gain 1/2/3 uses of rapid slash. (effectively a free slash)

Zealous Conviction
„Gain an action point after slashing an impaired enemy without killing it.“ Effectively a free slash if you do not kill your target). Adv/Sup also grant +5/10% aim

Shadowlace
Gain 1/2/3 additional charges of conceal.

SECONDARY UPGRADES - GREMLIN

Blinding Protocol
Gain 1/2/3 charges. Reduce target aim by 50% for 1 turn.

Override Protocol
Gain 1/2/3 charges.Target ally is immune to one attack for a turn.

Distortion Protocol
Gain 1/2/3 charges. Cause the target to panic.

Mascot Protocol
Gain 1/2/3 charges. Grant an ally an action point.

Aegis Protocol
Gain 1/2/3 charges. Grant nearby allies 6 points of shields for 4 turns.

Squad Targeting Protocol
Gain 1/2/3 charges. Grant nearby allies 15% aim and critical hit chance for 1 turn.

Trojan Protocol
Increase hacking by 5/10/15.

Shock Protocol
Increase combat protocol charges by 1/2/3.

Blinding Protocol
Gain 1/2/3 charges. Reduces enemy aim by 50% for 1 turn.

Tripwire Protocol
Gain 1/2/3 charges. Reduces enemy mobility by 4 for 1 turn.

Super Capacitor
Gremlins deal +1/2/3 damage.

Triage Protocol
Gain 1/2/3 charge of revival protocol. Requires the revival protocol perk.

Satellite Uplink
+1/2/3 additional charges of Scanning Protocol. Requires the scanning protocol perk.

Shield Protocol
Aid protocol provides 3/4/5 points of shields for 3 turns.

Targeting Protocol
Aid protocol provides 5/10/15% aim and critical hit chance for 1 turn.

Mjolnir Protocol
+1/2/3 charges of Capacitor Discharge. Requires the Capacitor Discharge perk.

Bastion Protocol
Heal all allies within a radius of 5 by 1/2/3 points per turn.

Squad Targeting Protocol
1/2/3 charges of Squad Targeting Protocol. Gives all nearby allies 15% aim and critical hit chance for 1 turn.

SECONDARY UPGRADES – GRENADE LAUNCHER

I learned recently that these are supposed to go on the Technical's Gauntlet too, but I have not tested out all of these, to check if they really functions as advertised when applied. Airburst Fuse definitely works both for Rockets AND the Flamer.

HEAT Munitions
Grenade armor piercing increased by 1/2/3.

Corrosive Shrapnel
Grenade shredding increased by 1/2/3.

Grenade Launcher Trigger
5/10/15% chance that the shot will not cost an AP.

Liquid Explosives
Grenades have +10/20/30% crit chance and +2 more crit damage.

Danger Close Explosives
Grenade launcher radius +2, damage +1, range – 60/50/40%.

Longshot Propellant
Grenade launcher range +20/25/30%

Air Burst Fuse
Grenade launcher radius +0.5/0.75/1 tiles.

Frag Satchel
Increases frag grenade capacity by 1/2/3 per slot.

Smoke Satchel
Increases smoke grenade capacity by 1/2/3 per slot.

Hydra Barrel
Increases grenade capacity by 8/9/10 per slot, grenade launcher radius -2.5 tiles . (Affects only the grenade slot)

Plague Satchel
Increases gas grenade capacity by 1 per slot.

Riot Satchel
Increases flashbang capacity by 1/2/3 per slot.

Sapper Satchel
Increases capacity of all grenades in the grenade pocket by 1/2/3.

Pyro Satchel
Increases firebomb capacity by 1/2/3 per slot.

ARMOR UPGRADES

Fire Vest
Grants immunity to fire.

Poison Vest
Grants immunity to poison.

Acid Vest
Grants immunity to acid.

Tactical Sensor
+5/10/15 defense vs enemies within 8 tiles.

Reactive Sensor
Increases defense by 5% per visible enemy, up to 15/20/25%.

Blast Vest
+1armor, -50% damage from explosions.

Hardpoints
Decreases chance of being critically hit by 5/10/15%.

Flexweave
+1 mobility; Adv/Sup also grant +10/20% dodge.

Undervest
+1/2/3 Hitpoints

Mag Deflector
Decreases damage taken from advent magnetic weapons by 20/25/30%.

Energy Diffuser
Decreases damage taken by alien plasma weapons by 20/25/30%

Shield Battery
1/2/3 charges. Provides 5 shields for 3 turns.

Leg Servos
1/2/3 charges. +3 mobility for 1 turn.

Digital Camo
Decreases enemy detection radius by 10/20/30%.

Medivest
Passively heals the user by 2 points every turn, for up to 6/8/10 points.

Medi-Satchel
Increases medikit capacity by 1/2/3.

Smoke Satchel
Increases smoke grenade capacity by 1/2/3.

Spotter's Satchel
Increases battlescanner capacity by 1/2/3.

Riot Harness
Increases flashbang capacity by 1/2/3.

Rage Stimulant
Increases aim and critical hit chance by 10/15/20% when the user is injured.

Stimplant
1 charge. Increase mobility by 3 and armor by 3/4/5 for 1 turn.

Reactive Servos
+5/10/15% overwatch aim; allows to fire primary weapon back at any attackers

Absorption Field
Any attacks that deal more than 40/35/30% of the user's maximum hit points, will be reduced to that amount.

Shield Gate
Grants 1/2/3 points of shield, user cannot lose hitpoints when shielded.

SPARK BIT

Overclock Protocols
Limited-use-version of Overdrive; grants 4 APs. 1/2/3 charges

Spotter Protocol
Intimidate marks enemies for 2/3/4 turns.

Survival Protocol
Initimidate grants 1/2/3 Shield for 2 Turns.

Repair Protocol
Increase Repair Charges by 1/2 /3.

Rocket Reserve
Increase Rocket Uses by 1/2 /3.

Shrapnel Reserve
Increase Shredder uses by 1/2/3.

Napalm Reserve
Increase Flamethrower Uses by 1/2/3.

Elerium Reserve
Increase Blaster Launcher Uses by 1/2/3.

Plasma Reserve
Increase Plasma Blaster Uses by 1/2/3.

Burst Protocol
Increase Nova Damage by 3/4/5

Martyr Protocol
Decrease Damage Taken While Using Sacrifice by 40/50/60%.

Seige Protocol
Increase Bombard Charges by 1/2/3.

Spartan Protocol
Increase Hacking by 50/70/90%.

SPARK CHASSIS

North Star
Decrease Strike Cooldown by 2/3/4.

Stranglehold
Strike stuns enemies for 2 action points and increase defense by 20/25/30

Arm Servos
Strike damage increased by 1/2/3.

Shock Absorbent Armor
Decrease damage from enemies within 4 tiles by 30/35/40%.

Body Shield
Increase defense against the nearest enemy by 15/20/25%.

The Fire, Poison and Acid vest can come up here as well, although the fire & poison make no sense since the Spark is immune...