Golems also have 50% melee resistance as well.
Biomechs, Demons, Highlanders, bosses (I guess?), BFE Adult Arachnoid and Scrapjack have 50% sniper rifle resistances (Reptiloids in classics and BFE also take 3 shots from it and 2 in HD)
Some bosses (Larva, Mordecai) also have 50% cannon resistance.

Now these enemies are slightly less annoying, a welcomes addition.