Need help with reference cards

I have no idea where to post this but would I need a reference card for crossbreeds? Such as my roan scandi surprise I’m showing as a friesian sport horse (going friesian x quarter horse for it) but would I need a reference card for it? And if I do then where on earth do I find reliable images?

Odd crossbreds can sometimes be found on the horse sales websites, but for showing here you don't necessarily need a reference.

Thank you! Wasn’t sure so I thought there was no harm in asking.