Lex Luger & 808 Mafia drum kits are standard, then get free Just Blaze drumkit and you are ready to go. No matter how much you want to be unique with using house pack for making trap music, it won't work much... you can create something with same tempo and rhythm patterns as trap, but it won't be trap music because it will lack sounds that are signature for the genre and are specially contained in these genre-specific packs - you won't find 808s in trance pack, trap snares in DnB samples, sirens in Soul pack etc. Why to limit yourself using samples that doesn't fit the genre? I believe even with already milion times used packs/samples you can create something signature and unique if you give it the right processing/edit/idea - pick obvious "hey" chant, stretch it, filter it, or play it as an instrument in sampler and suddenly you've created something less obvious!
If you still want to use packs fro other genres, I'd start with dubstep packs - people often mix dubstep with trap, it fits well, you have whole genre built around it: "hybrid trap"
For nice percussion and random sounds I recommend deadmau5 Xfer pack. I also recommend getting some KRNE pack, he makes really cool sounds. then there is Wallmart drums by Cymatics (for free), that has interesting sounds in it too. Sometimes I even use KSHMR pack for soem trap stuff.
