Duergar murderbandits.
Bugbear and hobgoblin ambushes.
Summoned dretches plus (monstrous?) summoner.
Stray (damaged?) H'balan flesh monster left over from the anniversary breach.
Lesser thrall patrol.
Randomly placed portal that either drops one off in a randomized wilderness location, or proves to be an amusing trap.
Corrupted animatrons. You know the ones.
Goblin knights on dogback.
Rust druids.
Underwater substance cloud, functioning like a gas would but with more exotic effects.
Behemoth beetle!
Monstrous adventuring party, programmed to buff up.
An undead bard.
Colossal rock worm queen and family?
A roving pack of ghouls.
Deepspawn, that
queer entry in Malarite dogma, whose only attack is unlimited summoned monsters!