Really depends on what level you are playing, I like Graveknights, pair them with a lich or a vampire, and a bunch skeletons and zombies fodder and you have a great boss battle.

I like throwing some ruffians from the GM guide at the players. Snagging strike is really strong. They fit in well with any group of bandits, robbers, criminal organization of choice or as hired thugs for a noble.

Ropers are very good at denying movement. For the right party, even just one roper can be a challenge.