The moreparts mod can help depending on some things, The moreparts mod adds a hinge which can be used to make some complex sort of parts and motion, For drones you can't really have the plane sort, though the moreparts mod adds a rotor and balloons which can be used in atmosphere. here is moreparts:
MoreParts Mod they had a rover update but for more advanced rover stuff use this:
PicoSpace Industries' Utility Pack
Though as with most of these packs i always have the issue of reusability with staging, can be a bloody pain to stage hinges repeatedly. You could always make a mod to improve this though if you wanted to.