I've gotten a lot of mine from
@IronCarnage 's bootleg thread on here, where he links a great Mega Drive list. Basically, I find one on YouTube I like, and see if his Mega Drive has it, since it'll probably be better quality than YouTube'll give me. And if there's something missing, I can usually assemble something decent out of it from other soundboards from that tour.
Complete and utter side note: Doing a mostly complete X Factour of all soundboards was a beast though, looking for both high sound quality that matched the others I had as well as listenable performances by Blaze. Outside of the Eternal Flame boot (which is incomplete), the best soundboards were in South America where his voice was good and blown. So...I cut Trooper entirely, since I'm not sure there's a good performance of that anywhere in existence, let alone on a TXF soundboard.