Ballistics FX
A weapon FX library starting with 93 impact particles (small/med/large impact FX for 31 materials) with more to come. There are also ricochet FX, destruction fragment FX and a grenade launcher with shrapnel.
If you are making a game in unreal 4 there is a reasonable chance you may at some point feature projectile weapons. Irrespective of your games genre (first/third person, RTS, adventure, anything!) when a projectile impacts something at high speeds you will invariably need impact particle effects.
Version 1.0 has 96 impact particles (small/med/large impact FX for 31 materials) with more to come. There are also ricochet FX, destruction fragment FX and a bonus grenade launcher with shrapnel. Update 1.1 added muzzle flashes/smoke, explosive canister blueprints, shell casing FX, a frag grenade, impact sound FX, a new material and improvements to the existing FX.