Varantic. Choice is good.

With Varantic, you can create real-sounding variations from a small set of sound effects.  Quickly and easily.

Varantic breaks sound effects into their sonic DNA, and it puts the sounds back together as probabilities.

Need a hundred different gravel footsteps? No problem. Need a ton of unique laser guns? Easy.  With Varantic, jobs that used to take days or weeks can be done in seconds.