Zombifier - Immortal medic
Everytime medic respawns, the medic respawns at the location the medic died the last time while equipping the zombifier, removing it from the loadout allows the medic to move on from the spawn.

SLASH! or Slashi - Any class's melee
Swinging the mouse affects the damage. The camera movement's velocity and the travel distance defines the "swing" parameter, and the melee damage is based on the swing parameter. Basically the user needs to flick the mouse, yet you have to click on the target mid travel, without interrupting the mouse movement. The max damage of 120. The camera movement is tracked to the last few milliseconds, and the travel distance between the last point of the record is used for taking the velocity, moving the mouse jig-zag does nothing. It could be exploited easily with thirdparty software though, the weapon is very fun to use.

Drunken Stainer or Drankenstain. - Demoman's melee bottle
Only able to attack during the charge. Primary fire allows him to drink the booze while not charging. Consuming the booze allows the demoman to refill the shield's charge instantly, that's only when he is equipped with the shield. When this weapon is equipped without the shield, the next hit with the melee becomes a crit. While this weapon is in the loadout, the movement speed penalty is applied regardless of whether the weapon is active. It might be better if the movement speed debuff is only when the charge meter is full.

Riverside beater - Demoman's punch
Allows him to refill his charge meter at +100% rate, twice the normal speed. But the damage is abysmal. When the shield charge is not in the full condition, a movement speed penalty is applied to the demoman.

Sanitizers - Pyro's alcoholic sanitizer.
He sprays an alcohol-based sanitizer. The vision distorts after getting sprayed, and the melee damage of any classes sprayed by this weapon is going to get lowered except Demoman. The spread of the weapons are increased after getting attacked by this weapon. This weapon deals no damage just by spraying. M2 alt-fire allows the pyro to throw a match, or something flammable. Or it should be limited to the use of the flares, instead of the sanitizer having the ability to ignite the opponents. M2 might be better being the traditional airblast. Attacks on the burning players ignite the spraying particles, or changes the weapon's current behavior. The tip of the sanitizer lacks the fire starter, so something burning is needed in the way to turn it into a flamethrower. Once the sanitizer's spray is ignited, the flame is sustained. Once the user stops spraying the weapon, it requires the fire starter to use the weapon as a flamethrower again. Maybe it should never be able to sustain the flame without the presence of the burning opponents. As long as the opponent is kept in the range it should update the afterburning status of the opponent. So I'm not sure about the requirement. If the pyro is holding m1 even after losing the enemies in the range, it might be better having the flames still intact. What if it only acted as a flamethrower against already burning players. If one opponent is burning, the players around the burning player might get caught in the fire so. The point is to not get close to the burning teammates. This idea is to have fun with the "Don't get close to me you are already infected" kind of zombie role-play. The silly and not-so-good way is just "burning players will ignite the teammates in contact", this is just silly and only works under the intention of griefing. This weapon deals no more damage than a standard flamethrower, it just changes the behavior.
The upside should be a longer traveling distance of the particles, until the particles are ignited. The alcohol mists should travel longer than it is when ignited.
The alcohol mists's vision disorientation effect should be on par with the Jarate.
There should be a dose level and if the dose level reached its critical level, the mercenaries insta-die with their own respectable set maximum tolerable amount of the alcohol. To reach it, the mercenaries are exposed to the mists continuously. As I said the mists itself doesn't deal damage at all, and the mercenaries can lower the dose level naturally.

Options on the transition of sanitizer to a flamethrower.
Option 1, Only flame particles are ignited after the contact with the burning enemies.
Option 2, Particles contacting the burning players changes the status of the weapon to a flamethrower and the particles released after the status change is also changed to flame particles from the start.

The behavior of the flame in the case of the Option 2 in the previous options.
Option 1, the flame requires the continuous presence of the burning enemies to keep the flame alive.
Option 2, as long as the spray of the alcohol mists are turned into flames, holding m1 keeps the fire alive.

The afterburn options
Option 1, Afterburn status is never updated by the particles
Option 2, Update the previous afterburn with very limited one. 1 second afterburn.

The first options changes the behavior on the enemy's positioning. As long as the burning opponents are beyond the nearby enemies, the nearby enemies just get sprayed with non damaging mists. In case only the particles are switched between the status. In the case of Option 2, The fire feeds back to the nearby enemies. The first option is more fun for everyone, including the enemies. But the second option is more logical in terms of implementation in game, if I ask you some practical things.

The behavior of the flame availability is better depending on the current presence of the burning enemies, I don't recommend just allowing the pyro to keep the fire alive by holding m1.

The afterburn status update is just needed with much more cares. If the enemy is already in the full afterburn by other pyros. Updating it with a very weak one is gonna ruin it. Option 1 grants the same goals, with slight differences in the results.
I mean by "other pyros" is that the afterburn caused by somebody else can be enhanced with weapons, though the afterburn can be enhanced by oneself.

Although the maximum dose level. Whether the value of the critical amount of the alcohol should be taken from the default health of the each corresponding mercs, or not. If it's against already damaged enemies, the normal flamethrower would be better at taking the final blow. But again, it has the extended range. So it's okay for this weapon to take more time against already damaged opponents. If the user of this weapon is not relying on the ignited particles, the user should focus on the critical dose level.
Why I bring up "1 second afterburn overwriting" is because it can be used to force the pyro to keep tracking the enemy in order to ignite the particles, without losing the firestarter. But if the alcohol dose can't be increased further more when the particles are already turned into flames, then it's going to struggle with allied pyros trying to ignite enemies. So even the ignited particles should contribute to the dose level. Sidearms are always going to be flares. Using a shotgun in conjunction would be not so efficient. The mist dose should be fixed on 1 per hit, and the critical dose level should be adjusted to that. Without changing the time it takes to bring down full health enemy with a normal flamethrower. The dose functionality can ultimately be omitted.

Trainner, Steamroll trainner, or Fuel rod. - Pyro's melee (Charcoal hammer, a wooden stick stuck together with multiple charcoal rods like a hexagonal terrain stones. I mean 3D stone hex tiles)
Attacking burning players will add +2 burning damage per tick, each time adds to the amount of medkit required for extinguishing the player. Medic's healing is affected by this. Or make it impossible to extinguish the fire for 5 seconds, while keeping the burning players able to heal themselves. As long as the rate of the healing is exceeding the afterburn damage, it just forces players to consume the supplies.
Maybe the idea I'm gonna include in this concept can be separated for an another weapon. When attacking against non-burning players, the player is applied with an effect "combustible". When the enemy is combustible, airblasted players explode upon the impact hitting the walls. The airblasted opponents themselves become explosive projectiles. The damage is based on how many times the opponent is attacked from this weapon, or it could be based on the remaining HP. But having the remaining HP as the basis for the gimmick damage is for balancing spy weapons I think, it should never be the option for a pyro weapon. Whether the exploded player should insta-die or not is up to the balancing, but I do think it would feel better if the blasted opponents just died from the attack alone. There is a need for the guidance to collide the opponent into the wall anyway. So it can be like a cliff kill but the situations are more common for the pyro. I'm not sure about having the velocity of the opponent as a basis for the explosion damage as it can be just random. For a proper balance, it should require more than just hitting once and airblasting the opponent, at the same time the explosion should kill the blasted opponent in one-hit regardless of the remaining HP. The best way to adjust this weapon is to just make it impossible to to be used this way while the enemy is burning or even getting ignited prematurely should ruin the explosive property of the enemy player. The airblasted player hitting another player must cause the explosion too. It's named this way because it's supposed to make people run like a train, hence the name "trainner" instead of just spelling it "trainer". Players attacked by this weapon while not burning shoud visibly be dusty, to warn nearby teammates.

Deadliner - Scout's execution pistol
When you are switched to this gun, the execution gauge starts filling up. The point-blank headshot damage from the behind is increased based on the execution gauge. But firing the pistol keeps lowering the gauge. The completed execution from the backside&headshot is gonna reset the execution meter to 0. The scout has to switch back to his other weapons for atleast once to be able to restart filling up the execution gauge. Base damage of 12, the execution damage's max ramp up is 120 damage. It takes just 2 seconds to fill up the gun completely. Each shots are completely accurate, but it has a significant damage dropoff. It deals mini crits damage against the head. Basically it deals 162 damage with one hit. The execution has to be done within the position the scout is almost touching the opponent. This gun has no spare magazine. It holds 12 rounds. I guess it should have 2 spare magazines. CL_autoreload toggling might be common but, the weapon no longer reloads automatically. Either the player has to empty the magazine or press reload key to initiate the reload. The manual reload should have no problem.

Carton - Scout's pistol.
Reloading adds 1 extra ammo inside the clip each time. He keeps reloading the gun until it's truly max. When the pistol is emptied it reloads 7 rounds in a go. Max ammo of 15. When the ammo inside the clip is beyond 7, even if the max ammo inside the clip reached beyond 9 for once, it still adds 1 ammo at the time. When the ammo inside the clip is below 7 rounds, it's gonna reload until it's 7 rounds in a go, within one reload. The name might be better being 1 stack magazine or 1 stuck magazine.

Exclamator - Demoman's launcher lier
Main-fire lays down stickies like normal, but holding m2 starts firing the propellants. The propellant itself doesn't have any damages much like the sticky jumper, but it propels the normal stickies. The propellant explodes when the demoman stops holding the m2 button. The detonation occurs right after the last propellant is grounded, this way the last propellant exploding mid-travel no longer disorientate the trajectory. The launched projectile stays the same as the normal stickies, Tapping or holding the m2 detonates the normal stickies previously layed down. It's a 2 stage fuse. Meaning the demoman is required to tap twice to detonate the normal stickies, essentially creating a room for the propellants to get laid down before the stickies explode. Propellants are fired exclusively quicker than the normal stickies, 70% faster firing speed. The stickies damages are pretty normal. But the propellants can launch multiple projectiles at the same time. Normal stickies are launched with very slow projectile speed, meaning it requires the additional propellants to deliver the stickies to far away. The stickies have a built in resistance to velocity aided to the vertical vector. The stickies should travel horizontally most of the time. But for the stickies to not touch the ground it should float above the ground ever so slightly. Maybe the stickies should never be "Sticky" against the ground nor walls to begin with, this way they can just roll around the collisions. The Demoman launched from this propellant causes colliding damage on contact with the opponent, based on the velocity gained from the propellants. But it might be hard to account the velocity gained from the propellants only, normal stickies used in the conjunction aiding the velocity might be fine allowed to increase the colliding damage.

Exclamator - Demoman's launcher lier
main-fire lays down stickies like normal, but holding m2 starts firing the propellants. The propellant itself doesn't have any damages much like the sticky jumper, but it propels the normal stickies. The propellant explodes when the demoman stops holding the m2 button. The launched projectile stays the same as the normal stickies, Tapping or holding the m2 detonates the normal stickies previously layed down. It's a 2 stage fuse. Meaning the demoman is required to tap twice to detonate the normal stickies, essentially creating a room for the propellants to get laid down before the stickies explode. Propellants are fired exclusively quicker than the normal stickies, 70% faster firing speed. The stickies damages are pretty normal. But the propellants can launch multiple projectiles at the same time. Normal stickies are launched with very slow projectile speed, meaning it requires the additional propellants to deliver the stickies to far away. The stickies have a built in resistance to velocity aided to the vertical vector. The stickies should travel horizontally most of the time. But for the stickies to not touch the ground it should float above the ground ever so slightly. Maybe the stickies should never be "Sticky" against the ground nor walls to begin with, this way they can just roll around the collisions.

Trembling souls - The Demoman's TNT launcher from MInecraft
The stickies don't go any further than his foots, barely able to lay down stickies in a normal use. The first sticky placed is a specially strong one, not getting destroyed from the first alt-fire when more than 2 stickies are placed. Next stickies propel the first sticky, technically it propels any other stickies but they get destroyed. Either the first sticky should be buffed based on the amount of the propellant is up to the balancing but, it should be fun. The first sticky is able to be detonated from the second activation of the alt-fire. Demoman launched from this "cannon" is given a colliding damage based on the velocity.

Exlair - Spy's slide moveset
Tapping A or D key twice quick enough allows the spy to slide sideway in a rapid motion. The moveset is activated via equipping the weapon owning this stats. But what weapon slot should it be is up to the weapon itself. As multiple weapons could have stats based on the weapon's viability. If the weapon having this stat is stacked, it could allow the spy to slide multiple times without resting. It should be limited by the stamina meter. Instead of allowing forward&Backward slide too with the same weapon, the weapon designed to allow F&B direction slide could be separated. Taking up the different stamina meters, or sharing the meter for 2 different stats when used altogether. I think they should share the stamina though. The meter is like Jetpack for the pyro, having multiple weapons with this stat adds to the count. It can be performed only when the spy is grounded. Exceptionally, when the opposite direction of the spy's desired sliding direction is facing a wall, it allows the spy to slide regardless of the "grounded or air-borne" status.

Hot face - Specification
The main fire adds to the "Heat" meter, when the heat meter is reached full the pyro equipped with this weapon dies. Heat can be removed by either a manual airlblast or just waiting for the heat to lower. When the heat is higher, the airblast cost increases. Spamming the airblast keeps lowering the cost.
I know it's better being "When the heat reached its max, the pyro gets damaged continuously for keep firing the primary." But it makes it way too easier to manage the heat, as the player can just stop firing after realizing the self-sustained damage.
+10 fuel per second, the ammo boxes nor dispenser, cart no longer refill the primary ammo. Airblast cost at 0 heat is 10. The airblast cost at 80(Theoretical number only) is 90. The attainable heat limit in game is 79. Firing the weapon for 80 ammo equivalent is 80 heat. 1 ammo consumed means 1 heat increased. Adding "m1 can't be fired right after airblasting for 2 seconds." it might be better being 2.5 seconds. Also the name might be better being Hot Faith

Karateka - Spy's cutter knife
Self-damaging weapon. While cloaked the user can initiate the self harm, if the user is already disguised, the disguised player's HP others are going to see is also lowered. It's good for calling for medics. Also it might be better having the same stats as the another weapon of the similar concept, the HP faker. The spy's teammates attacking the spy fakes the spy to be getting damaged, even though the spy is not actually sustaining the damage. The fake stats indicated for others are affected by the attacks initiated by the spy's teammate. The blood should be visible, whether the knockback should be there or not is questionable, but what I believe is it can cause certain issues like failed stabs. So the knockback shouldn't be applied from the spy's teammates. The HP faking revolver did not have the capability to actually damage the spy. But this knife damages the spy too. Maybe the sole stat of "Actually damaging the spy too in order to lower the indicated HP of the disguised player" should be transferred to the revolver instead.

Mellow Rhythunder- Pyro's double barrel flare
Loads 2 rounds. Crits against burning players. When the pyro misses the second shot, the pyro gets damaged for 90 damage. Off the limit.
The name might be Raythunder. Or even Mellow Mellow.

Mellow - all class shotgun
Single barrel shotgun, basically flare without the burn type damages. fixed 60 damage at any range.

caritas - Spy's invis watch
When the undisguised, uncloaked spy gets close enough for the approximate range of other players, the enemy is nerfed in a certain way. This is to make it easier to fight off players after failing to stab. Pyro loses the ability to use the fire of the primary until he touches his teammates. Meaning it still allows the pyro to airblast. Other classes lose the ability to use the primary for 5 seconds. It has no cloak duration limit but the usage is limited by how many times the spy can toggle the cloak. This weapon only allows cloaking for once.

Pecca - Spy's disguise kit
No longer tracks the kills on the killfeed. It's hidden except for himself. But when other players found the location where the teammate remained last, the players are notified with the kill. Essentially "Reporting" the kill. But to compensate for this delay, the killfeed appeared after finding the already dead merc comes with the timer indicating how long it lasted before getting found out. Also the players already respawned are never notified. The downside is, none. But some players might prefer notifying others for what he did.

Gloomy ambient dust - Only able to m2, m2 creates a huge explosion. It also damages the pyro. Instead of reflecting projectiles, it causes the in coming projectiles to explode together. As much as damage is casted upon the explosion. M1 might be allowed but it should instead spray dust particles that will enhance the explosion damage later on.
The detection method for the induced explosion is better being based on airblast detection box. But if it's technically hard to implement, Short circuit's projectile-deleting ball might be a shorter way. It should not cast the normal airblast knockback at the same time. If it's synced, 2 knockback sources add up at the same time. The knockback gets too strong. So either it only allows the airblast knockback with the knockback disabled for the explosion or just not having the airblast knockback should be more practical. As the blast going all the way would be a more suited representation of the weapon.

Dizzle dolizle - Soldier's primary. The projectile behaves like a snake. They wave up and down, not horizontal. Maybe it should wave horizontally too. Unlike drifting it changes what direction the rocket is facing based on the vector.

Daisy - Demoman's drone. They stay airborne. The demoman can shift the view into the drone and take a full control of the drone. Otherwise it won't do anything. The drone explodes on the whim. The drone can be intercepted fairly easily but it still explodes even after falling into the ground.

Alchimedeath - Medic's primary, the previous post didn't clarify the concept. The strap bomb on the Archimedes basically. The weapon can be launched from the medic's arm, the weapon stays on the medic's shoulder like a cosmetic. The damage is 170. After chasing the target like a homing missile, the missile stops chasing the target when the mission is deemed failed. And the pigeon missile tries to go home, in this case, the medic who launched it. So it's a forced hit-or-death. the projectile can be intercepted with any damaging weapons. The pigeon tries to dodge the walls as much as possible. The pigeon's sense ignores the walls but the pigeon has a maximum turning angle, meaning it's better changing the course at the near-hit moment rather than just strafing the whole event. It's a one time use event unless taking the respawn cabinet. The medic's respawn is necessary for taking this weapon.