AIC - facelift (was that 89 or 90?)
Motorhead - Bastards and 1916
Testament - Demonic
Black Crowes - By Your Side
Sepultura - Roots (real natty but in a good heavy way)
Zakk - Stronger Than Death and Sonic Brew/tality?
Neurosis - Enemy of The Sun and Times Of Grace
Buck Cherry (don't love the band but they get good tones)
Slayer - Diabolus
Masters of Reality ST
Raging Slab - Dynamite Monster Boogie Concert
Heaven and Hell - The Devil You Know
Dropkick Murphy's
Death Breath - Stink Up The Night
Entombed - several records
Hellacopters - several records
Lots of Metal bands from Scandanavia and Germany
the more i started thinking about it the more I realized there are a ton of good tones since '90
Crap, just realized you said tone, singlar. Sorry couldn't pick only one.