Hey buddy - Engineer
While grabbing the buildings, the frontal damage is absorbed by the buildings. The box kind of works like a shield. PDA. Any reasonable negative stats to balance out.

Charging airblast - Holding right click charges the next airblast
The airblast lasts for 0.2~0.3 seconds at max charge. The airblast cost depends on the charge time. The main attack lasts for 2 seconds consecutively, the main attack has a cooldown time. If the airblast is used, the main attack cooldown is slightly reduced.

Ascendants - Demoman's shield.
Knocks back enemies on ramming, he doesn't stop from colliding with anything. 70% fire resistance, 15% explosive damage resistance, 10% bullet damage resistance. The collision is temporarily disabled between the players to avoid a clipping.
Priced will - or valued will. Rifle for a soldier to roleplay as a deathmatch mercenary stereotype. Basically a smg that does a mini-crits on headshot, 30 round magazine. The accuracy is based on the moving speed of the character using it, not by the ups but in %. 0% movement speed means a perfect accuracy in automatic fire, 100% moving speed accuracy means the typical smg accuracy. The damage is the same with the default SMG. This gun has a specific function named "too far away" it's a status effect applied to the enemies fired upon the range. Basically, even if the round is hitting the enemy, the enemy doesn't take any damage and instead display this message telling it's too far away. Just like when enemies are bonked, it's displayed so that's it's easier to notice if it's the aim or the distance. Crouching removes this range restriction regardless of the moving speed. The full crouch is required to take the effect. This is to simulate the sniper's slow movement speed in the zoom. So that it's a mix between marksman rifle and SMG. A sub variant can be created by forcibly disabling the automatic reload and managing the remaining ammo by how many times the user can reload the weapon. So that the remaining ammo in the discarded magazine is not recycled. 3 or 5 magazines should be enough, it's about 90 to 150 round in reserve. The increase in the range might be better being gradual, so that actively firing while starting to crouch would get a slightly smoother transition of registering the damage.

Ascendants - Demoman's shield.
Knocks back enemies on ramming, he doesn't stop from colliding with anything. 70% fire resistance, 15% explosive damage resistance, 10% bullet damage resistance. The collision is temporarily disabled between the players to avoid a clipping.
Valued will - or priced will. Rifle for a soldier to roleplay as a deathmatch mercenary stereotype. Basically a smg that does a mini-crits on headshot, 30 round magazine. The accuracy is based on the moving speed of the character using it, not by the ups but in %. 0% movement speed means a perfect accuracy in automatic fire, 100% moving speed accuracy means the typical smg accuracy. The damage is the same with the default SMG. This gun has a specific function named "too far away" it's a status effect applied to the enemies fired upon the range. Basically, even if the round is hitting the enemy, the enemy doesn't take any damage and instead display this message telling it's too far away. Just like when enemies are bonked, it's displayed so that's it's easier to notice if it's the aim or the distance. Crouching removes this range restriction regardless of the moving speed. The full crouch is required to take the effect. This is to simulate the sniper's slow movement speed in the zoom. So that it's a mix between marksman rifle and SMG. A sub variant can be created by forcibly disabling the automatic reload and managing the remaining ammo by how many times the user can reload the weapon. So that the remaining ammo in the discarded magazine is not recycled. 3 or 5 magazines should be enough, it's about 90 to 150 round in reserve. The increase in the range might be better being gradual, so that actively firing while starting to crouch would get a slightly smoother transition of registering the damage.

Keep me grounded - Soldier's shoes
Usage : I don't know
The user can't be knocked back. The movement speed penalty is 15%.
The player can't rocket jump due to the disabled knockback.
Jumping height is not affected. Airblast immunity is added to the soldier himself.
The fall speed accelerates mid air, the damage on stomping on someone else is almost always lethal. Basically a heavy boots from Zelda series.

Aquatic sky - Spy's roof clinging device
It's a revolver without the gun functionality.
It allows the player to jump higher on fire button. If the player hits the ceiling, the spy can stay there upside down. The pose is like a frog. Player can descend at will.

Goodwill. Spy's cloak watch without the increased damage resistance.
This cloak watch gives the player 50 more HP by default, under the cloak's effect he is instead given a shield with its own HP. How spy dies is determined by the shield. So if the player has like 30 hp, and cloak. The spy only tanks the defined number regardless of the HP. Shield gained by the cloak itself has its own HP. When the shield runs out, the spy dies.
Shield is charged slowly. The shield's suited HP is debatable, 70hp might fit.
Even if the player is at full health, the spy dies when the shield is set to 0. If the damage exceed that limit, the spy dies regardless of the HP. So it's better for the user to turn it off manually before dying of the shield mechanics.

I thought a striking name but forgor so no placeholder name to even top that.
Spy gains 30% more HP, or gain 30% damage resistance instead. The cloak gives the spy reduced damage resistance of -50%. 50% the default, not after adding the 30% damage resistance.

The dying sun
Pyro's long finisher move
Melee weapon that everytime you hit enemy with it, the coupling taunt will play. If the animation completes, the enemy dies. But the animation takes long like the arrow taunt, gunslinger. If the taunt is interrupted by a damage exceeding 30, the taunt is cancelled. But the point is, it's just way easier to enter the stun lock. The animation can be varied, but the general idea of mine is that the pyro stranglehold the opponent in the neck. The idea brought from SCP SL. The damage can be applied over time with the time-based finish. But it creates the problem that after surviving the attack it's hard to counterplay with the remaining HP.
Absolute animal
Pyro's fox tail burner. M2 changes the direction of the fire. Changing the direction of the nozzle flips the entire flamethrower, this causes the weapon to produce a broom like swinging attack. The flames of this weapon produces tremendous amount of thrust. Making the pyro move in the direction. This weapon is good for the mobility but the damage is bad. Instead of flame particles, this weapon produces a "beeds-through-the-line" style hitbox. few boxes are created in the way of the box. Trying to fire in front slows the user from moving forward. Pyro can flip the flamethrower to chase players but they don't produce the frontal AoE.
Slogan
Pyro's flamethrower that can take damages
Pyro's flamethrower has its own hitbox, if the flamethrower gets damaged by the gunfire, the damage will add up and weaken the flamethrower. Recovers over time for not firing. This flamethrower can just wipe out stickies. The base flamethrower can simply break the laid down stickies without exploding them by continuously firing at them. +50% damage for buildings.

Mammal factory
When teammate dies near the buildings, the buildings are healed overtime. The ability can be added to any slots.

The dying sun
Pyro's long finisher move
Melee weapon that everytime you hit enemy with it, the coupling taunt will play. If the animation completes, the enemy dies. But the animation takes long like the arrow taunt, gunslinger. If the taunt is interrupted by a damage exceeding 30, the taunt is cancelled. But the point is, it's just way easier to enter the stun lock. The animation can be varied, but the general idea of mine is that the pyro stranglehold the opponent in the neck. The idea brought from SCP SL. The damage can be applied over time with the time-based finish. But it creates the problem that after surviving the attack it's hard to counterplay with the remaining HP.
Absolute animal
Pyro's fox tail burner. M2 changes the direction of the fire. Changing the direction of the nozzle flips the entire flamethrower, this causes the weapon to produce a broom like swinging attack. The flames of this weapon produces tremendous amount of thrust. Making the pyro move in the direction. This weapon is good for the mobility but the damage is bad. Instead of flame particles, this weapon produces a "beeds-through-the-line" style hitbox. few boxes are created in the way of the box. Trying to fire in front slows the user from moving forward. Pyro can flip the flamethrower to chase players but they don't produce the frontal AoE.
Slogan
Pyro's flamethrower that can take damages
Pyro's flamethrower has its own hitbox, if the flamethrower gets damaged by the gunfire, the damage will add up and weaken the flamethrower. Recovers over time for not firing. This flamethrower can just wipe out stickies. The base flamethrower can simply break the laid down stickies without exploding them by continuously firing at them. +50% damage for buildings.

Mammal factory
When teammate dies near the buildings, the buildings are healed overtime. The ability can be added to any slots.

Dirty Dank little Hole
Sniper rifle, you can have a X-ray on the sight of line you shot. The general direction you fired your gun gets a detection cone. If enemy is in the cone, no matter the range or the walls, the player gets the see through vision of enemy locations. The cone lasts for 3 seconds.

Spy's tag revolver. Basically an unnoticeable paint ball.
Spy can hit players with a non-damaging revolver, it marks players to be visible through walls , at certain distances. But the punishing element is, if the spy misses his shot, it creates a puddle of paint on the wall or the floor. Also, this gun can not be fired under the disguise, just like any other official revolvers.

The innocent king, heavy's medigun.
It's basically a medigun for heavy. The difference is that the player needs to aim his guns constantly. Also the rounds are piercing, so the player can heal multiple players in the general direction.

The empress of light - Soldier's banner
Under the effect, all damages to the soldier is reduced by 75%. But after the banner effect runs out, all the damage he was supposed to take is applied to him. Killing him in the most case scenarios. So if you take 100 damage, under the influence in the banner, he takes 25 damage at the moment. As the banner lasts 10 seconds, his remaining 75 damage he should have received is added up. But instead of instantly dying, the damaged is applied over time at the last seconds. Like 2 seconds, and all the damage is applied. There is a slight chance he might survive it because a friendly medic out heals him.

The complicated blues : sticky launcher with no visual indication. It's really hard to avoid getting hit by it. Only able to load the round when the demo defeat another player, so that its use is limited one time per kill. Also if you stay without firing the round for 5 seconds, the loaded round is removed. Meaning you are forced to fire as you defeat someone else.
It's not worth it.

High tower : Basically the mannhole I wrote like half a year prior. But with the ability to move around underground, actually it's represented to be moving through the underground. The camera position is lowered significantly and the player model disappears temporarily but it's just a thing in visual. So the player is actually following the terrain. The player can't gain ubercharge for a minute after the use of this weapon. If this is to drain the uber, certain weapons would have a better gaining speed in the ubercharge. So by making it this way. The uber consumed in the sense is worth the length of time.

Dirty Dank little Hole
Sniper rifle, you can have a X-ray on the sight of line you shot. The general direction you fired your gun gets a detection cone. If enemy is in the cone, no matter the range or the walls, the player gets the see through vision of enemy locations. The cone lasts for 3 seconds.

Spy's tag revolver. Basically an unnoticeable paint ball.
Spy can hit players with a non-damaging revolver, it marks players to be visible through walls , at certain distances. But the punishing element is, if the spy misses his shot, it creates a puddle of paint on the wall or the floor. Also, this gun can not be fired under the disguise, just like any other official revolvers.

The innocent king, heavy's medigun.
It's basically a medigun for heavy. The difference is that the player needs to aim his guns constantly. Also the rounds are piercing, so the player can heal multiple players in the general direction.

The empress of light - Soldier's banner
Under the effect, all damages to the soldier is reduced by 75%. But after the banner effect runs out, all the damage he was supposed to take is applied to him. Killing him in the most case scenarios. So if you take 100 damage, under the influence is the banner, he takes 25 damage at the moment. As the banner lasts 10 seconds, his remaining 75 damage he should have received is added up. But instead of instantly dying, the damaged is applied over time at the last seconds. Like 2 seconds, and all the damage is applied. There is a slight chance he might survive it because a friendly medic out heals him.

The complicated blues : sticky launcher with no visual indication. It's really hard to avoid getting hit by it. Only able to load the round when the demo defeat another player, so that its use is limited one time per kill. Also if you stay without firing the round for 5 seconds, the loaded round is removed. Meaning you are forced to fire as you defeat someone else.
It's not worth it.

High tower : Basically the mannhole I wrote like half a year prior. But with the ability to move around underground, actually it's represented to be moving through the underground. The camera position is lowered significantly and the player model disappears temporarily but it's just a thing in visual. So the player is actually following the terrain. The player can't gain ubercharge for a minute after the use of this weapon. If this is to drain the uber, certain weapons would have a better gaining speed in the ubercharge. So by making it this way. The uber consumed in the sense is worth the length of time.