I have no idea, but I'd like to see other people's ideas! When my brother & I were born my Mum picked really obscure god parents, for reasons I cannot fathom. But my parents' best friends were listed on their will to take us if anything should happen to them, and we called them Aunty & Uncle. To be honest we've always been closer to them than any of our actual aunties & uncles, and definitely closer than our god parents!! I reckon our children will call our close friends aunty & uncle, I kind of like it