NPCs emulating character classes are many. A very incomplete list would include: Abjurer, Archer, Blackguard, Bard, Champion, Conjurer, Diviner, Druid...
You get the idea.
Among the monsters there's the Hobgoblin Iron Shadow and the Shadar-kai Shadow Dancer, but I'm struggling to find Monks among the NPCs in the sources I own so far. I'm hoping to represent various Monk subclasses in NPCs, and I'm looking for the balance that I attribute to the officially-made NPCs.