Add your ideas below and I will edit them in
HBAR: Delays damage drop-off.
Bayonet: Increased melee range, but slower stab.
Stock: Increased hip-fire accuracy and slightly lower recoil (though not as much as grip). Increases draw time substancially.
Dual triggers - allows both barrels to be fired off with one shot. Exculsive to the Olympia
Slugs: Increases shotgun range and accuracy but drastically reduces power.