"Pet Sounds" is a great instrumental that I've put on several mixtapes
And though "Bad" obviously isn't one of MJ's best cuts, it's ok for what it is. I'm with you re: "Small Change" (never been much of a fan of that album in general though except for "Step Right Up") and "Kid A" (Radiohead pretty much suck at instrumentals- yes I know there's technically a vocal here, #### off) though.
"Weasels Ripped My Flesh" is the first thing that popped into my head but it's not really a song and works perfectly in the context of the album. I always let it play even though it kills my ears.