Many ideas I post were used in many games and mods but, I think they should be useful
* Flamethrower
the flamethrower is a classical weapon and the special mod is to use it as a jetpack, the jetpack uses ammo of course, but the tool function is a transportation mode
It's concept is a weapon with two shoulder flamers (we hve a third little flamer on the right arm but it's only used in jetpack mode) the shoulder flamers will be used as thrusters in jetpack mode, and it has a lot of recoil
* Freezegun or freeze thrower
Originally from duke nukem 3D this gun can have a tool function is to create icebergs on the water and walk on it, like a flamthrower it doesn't work properly under water, the freeze plasma is used to create icebergs, the gas is the most dangerous thing because it can freeze immediately the player, the Cristal mode is the most secure mode.
the plasma is for icebergs, the gas is for the water routes ....
* Portal gun with grav gun
Many games has this as a mod, originally from the game Portal, The best tool function is to combine it with a gravity gun.
* Combining a lightening gun and a water cannon (Hydro lightening cannon)
Disabling machines or make traps this weapon can be a must
* Construction gun
Idea from U4E 2004 the idea is interesting, bu I think we can build for example crates, bombs, mines or eventually structure elements
* Hoverboard shield
This is a standard shield with an hoverboard function, in Hoverboard mode we can't use its protection, but it gives speed
* Multi utility launcher
An idea from the last chaos UT ans gunreal, this can launch hand grenades, mines, projectiles, drones, eventually translocation devices, disks, cameras, remote turrets and many things .... we can imagine a grapple function of course
* Rocket launcher
A crazy idea but flying with a rocket launcher can be "fictionally possible" if the weapon keeps the rocket in the tube
we can fly or make a great jump, and eventually use more ammo fly and do kamikaze
It's a bit different than the strangelove mode, beecause this mod allow us to ride a missile ....
* Throwing disk
An Idea from TRON 2.0 it's a disk with a shield function, or eventually like the UT translocator teleport yourself in the disk
* Pick Axe
A weapon but we can use this to climb walls
* Wind cannon
Uses wind to push things and enemies into wall and eventually can be used as a jet pack
* Arrow - spear launchers
Use these weapons as grapple launchers or to create a way with a rope
* Flashlight
Simple idea, to blind our foes and have the ability to make light in dark places
* Flare pistol
to make light sources and burn enemies or other things.
* syringe launcher
to cure or kill melee or distant
I don't know but I think guns with other functions is cool even if sometimes it's only tools like the flashlight ....