Other things:
Gas grenades (A small correction for mmartinjj, additionally, your vision will blur while you're in the gas mist, doing extra damage overtime)
Flash bangs
Ballistic shields (Inspired by Ghost Recon, can block bullets and rockets out for 10 secs, blocks out enemies from coming through but not teammates)
Optical Camouflage (Inspired by Ghost Recon, this works like the ones for CS Ghosts, you will become invisible for 15 secs, automatically disables when you get shot, but it never disables when you shoot)
Shock Grenades (Designed to stun everyone, very effective when used underwater, will disable battlesuits, leaving the victims vulnerable to attacks)
Camera Drone (Credits to Captain Epsilon Tex, including LazyRain's ideas for the drones also)
Heat Suppression Drone (Additional idea for Cpt. Epsilon Tex, can damage enemies for about 20 secs, overtime)
Laser Locator (Works like a radar scanner, use it for pinpointing enemies so your teammates know where they are)
Laser tripmine (Inspired by Half-Life & Battlefield Hardline, this can blow up when someone passes through the laser unaware of any explosives deployed)
Tracer Pistol (This weapon gives you and your teammates a chance to target enemies without struggle, so automatically, the enemy will show up on the minimap, it lasts for 2 mins, but it can be destroyed quickly when it's submerged in water)