Somone already touched on this but if you get bored with, for example, your same 3 Marro Drones then carve some of them up! Seriously, just a simple arm-switching here and there and you suddenly have 6 new sculpts or more! Or head-swapping, weapon-exchanges, etc.
Same thing with zombies, orcs, kyrie squads, monks, etc.
I have almost ZERO modding talent and even I can do this.