Shotguns: Bolo rounds, Dragons Breath shells (both slugs and buckshot), slugs, Flechette, exploding tip, buckshot, birdshot
Rifles (and some heavy and smg's): Incendiary, Armor Piercing, Regular (like just the normal for whatever caliber it is), Incendiary Armor Piercing (yes all in one lol), Tracer equipped (like your normal ammo plus having tracers in the mix)
Grenade Launchers: HE, Fragmentation. White Phosphorous, Fuel Air Burst, Stun (like less damage in game but knocks them down longer), Flash, Sticky (like somehow make it slow them down with some kinda sticky substance around the area)
Pistols: Same as Rifles but less damage of course.