The Possibilities for this are pretty broad, but here are my suggestions.

Would Add reduced Sway and Recoil.

Angular Grip - AK, M4, other Railed Weapons
Standard Foregrip - AK, M4, other Railed Weapons
Combined Foregrip/Laser/Flashlight - AK, M4, other Railed Weapons
Combined Foregrip/Bipod - AK, M4, other Railed Weapons
Wood Foregrip - AK {F32788} {F32789} {F32790} {F32791} {F32792} {F32793} {F32794} {F32795} {F32796}