What are some non-standard hair-color and class combinations that look really good?

Particularly, as children characters in Fates and Awakening get hair colors from a parent, they can have ones greatly different from their default appearances.

Sometimes these clash with the color schemes of the classes - sometimes these work really well.

What are some of these cases.

Example: Oboro gives people blue hair that kind of fits in with the generic blue classes of reclasses [like Oboro!Caeldori Spear Master] but at the same time might clash if compared against unique class appearances for that character [I think the blue given by Oboro makes Caeldori's custom red Sky Knight clash against it]

What sorts of examples can you come up with?