How prevalent are cross-breeds in the GFFA?

It just occurred to me that I can't readily think of any half-this/half-that characters in the canon. Not even half-humans.

I know the X-Wing books flirt with the idea of bispecies offspring, but doesn't "go all the way" with the concept.

Please leave a comment with any bispecies characters you're aware of. Also feel free to speculate wildly on what some hypothetical bispecial races could exist out there.