Here are a couple board games I picked up from clearance bins. They each have interesting mechanics which can be stolen and incorporated into tabletop rpg encounters.
Attack on Titan
BGG link. One-versus-all boss battle. Based on a show about fighting giant monsters called titans.
I picked this one up because I like the designer's other work. The main problem it has as a board game is that the titan's side of things isn't very engaging. If the titan was automated, then it could be a satisfying cooperative dice-rolling puzzle thingy.
But it had some really fun little ideas:
Climbing on the Beast:
First of all, the human characters move up and down these little cardboard standees. The ground counts as a space, as does each layer of the tower, and about half of the locations represent the humans climbing up the titan, shadow of colossus style. Some spaces allow you to do special actions, like firing the cannons from the tower, while others are places you need to maneuver to accomplish certain objectives.
This is just good fun. And you don't really need a 3d prop to accomplish this effect. Just lay up some index cards indicating certain points-of-interest atop whatever giant monster is being fought.