I honestly can't think of one. But truthfully I've been wondering forever why Diana doesn't get one. She's had two wondergirls, why not something like a wonderboy? She's motherly, and wants to teach man's world the Amazon way, a young boy would be a perfect analogue.
Make him like the son of an Olympian or someone who was burdened with a gift/curse through some ancient Greek ritual and boom.
I think the reason we don't often see male sidekicks to female heroes is soft sexism.