Stock Mods can help with Weapon Fire Rate and Recoil and well as a few that improve Melee Damage.

Explosive Impact Stock
Attachable to Rocket Launchers and Detonators. Mod Effect: Melee Damage.
Explosive Quickening Stock
Attachable to Rocket Launchers and Detonators. Mod Effect: Fire Rate.
High-Caliber Balanced Stock
Attachable to Bolt-Action Sniper Rifles, Semi-Auto Sniper Rifles, and Pistols. Mod Effect: Recoil.
High-Caliber Quickening Stock
Attachable to Bolt-Action Sniper Rifles, Semi-Auto Sniper Rifles, and Pistols. Mod Effect: Fire Rate.
Mid-Caliber Balanced Stock
Attachable to Assault Rifles, SMGs, and LMGs. Mod Effect: Recoil.
Mid-Caliber Quickening Stock
Attachable to Assault Rifles, SMGs, and LMGs. Mod Effect: Fire Rate.
Shell Balanced Stock
Attachable to Combat Shotguns, Pump Shotguns, and Sawed-Off Shotguns. Mod Effect: Recoil.
Shell Impact Stock
Attachable to Combat Shotguns, Pump Shotguns, and Sawed-Off Shotguns. Mod Effect: Melee Damage.
Shell Quickening Stock
Attachable to Combat Shotguns, Pump Shotguns, and Sawed-Off Shotguns. Mod Effect: Fire Rate.