I haven’t found any games that exploit this yet. Traditionally it has been very difficult to make games that feature truly large entities that behave actively and not in very broad and uninterested patterns due to things like camera constraints and what not. Shadow of Colossus and it’s siblings come to mind as close examples of this almost working. But VR could make it great.
While the bosses move in broad and uninterested patterns, I've found that Jet Island is a game that features very large entities which make great use of the scale vr allows.