Here are my concept arts, made with Paint.net (The drawings aren't that well, but I like the idea):
Ultra-Howizer Grenade Launcher:
Firemodes:
Flak: Explosive, releases shrapnel
Incendiary: Works like a napalm-bomb, burns the area and ignites enemies
Gas: Poison gas, which is nearly invisible and kills the enemies near the impact zone. Doesn't do damage against vehicles.
Freeze: Freezes the area and enemies. Kills enemies on direct impact. Enemies which are frozen, will be unable to move for a couple of seconds and take damage.
EMP: Damages enemies and shocks them for a couple of seconds, so they'll be damaged and can't see anything (works like kelly's tech grenade). Disables vehicles for a couple of seconds and deals the most damage against them.
Acid: Works like the Reptile's alternate fire. (blob)
Damages every enemy, which walks into the pool.
Sticky: Sticks to enemies and other surfaces. Explodes after a few seconds. (Beeps first)
Shockwave: Pushes enemies away and deals some damage. Very effective against small vehicles, like scorpions.
Plasma: Does a lot of damage near the impact area, and deals some electrifies enemies for some seconds.
Smoke: Creates a big cloud of smoke, which enemies can't see through. I supposed to work with bots (which won't work, I guess)
Homing Ball: Fires a ball, which lies on the ground, rolls around, depending on gravity and surface and follows enemies which come near it. It explodes, when it touches an enemy. Can be controlled with the laserpointer-mode of the U-H.
Radioactivity: Very dangerous. The projectile travels very fast, and is radioactive. It explodes when it hits a solid surface. The area will be corrupted for a long time and the radioactivity deals lots of damage. This firemode is dangerous!
Mine Mode:
The firemodes work the same, but instead of grenades, you can fire mines, which have the same abilities, but don't explode on impact. They explode, when an enemy is near them. Otherwise, they work the same.
Special Explanations:
Sticky:
Works the same, but only explodes if enemies are near it.
It's also the only one, which can stick to vehicles or persons.
Homing Ball:
Works the same, but sticks to a surface and only rolls, when someone is near it.
Also you can't controll Homing Ball-Mines with the Laser-Mode.
Radioactivity:
Same, but the projectile doesn't do radioactivity damage anymore.
EDIT: Crossbow:
CB-1200 "Multi-Crossbow":
There are many different Crossbows with different camouflages, like in Kelly's pack.
There's a normal Crossbow, a green one, a red one, a blue and many other ones...
The firemodes are only available for specific camouflages. I will mark them beneath.
Firemodes:
Normal: Fires a regular bolt, which deals lots of damage to enemies, but does next to no damage to vehicles.
Penetration: Penetrates enemies and does more damage against vehicles, but does less damage against single enemies.
Harpoon: Works like ninja rope. You can pull enemies to you or swing with it. Your choice!
Fire: Lights enemies on, but doesn't burn the whole impact area.
Poison: Does damage over time. Doesn't work against vehicles.
Explosive: Explosive. Does more damage against vehicles and can kill any enemies at once.
Ice: Freezes one enemy and deals more damage than a regular bolt.
Electricity: Electrocutes enemies and has a chance of 20% to disable a vehicle. Deals more damage against vehicles.
Magic: Same as a regular bolt, but is a one hit kill. Reloads slower.
Light: Isn't affected by gravity and travels very, very fast.
Napalm: Explodes on impact and burns the area.
Acid: Same as the secondary fire of the reptile.
Glacier: Explodes on impact and freezes the area.
