The secret to finding good files is to spend lots of time searching through the zillions of files, then saving the best ones. The easiest and one of the most efficient search engines for midi files is www.musicrobot.com

BTW, I've often heard folks claim that you cannot make a good midi file using the PSR sequencers. Well, maybe I'm just not a coneseur of midi files, but I sincerely believe it would be difficult to top those created by Will Stewart. You'll find them posted at http://psrtutorial.com/P/Stewart.html

Enjoy,

Gary