The one I refer to often is Sean Niland's VMS herp website.
Click on "our breeders" then "Leopard Geckos" and he has a pretty good list with pictures of most. This isn't a complete list of all of the combos that have been made but the base mutations are there.
I would recommend being very selective about what you breed because the Leopard gecko market is very soft right now. Up until last year I couldn't produce enough babies to meet demand, then last year I displayed at several shows and didn't sell a single gecko! This year I didn't even bother going to the shows. I just bred what I needed to keep my long term projects moving forward and kept all of the offspring.
Leo's are great little animals and I am sure they will regain their popularity eventually because of their superior qualities as a pet. But, for now, the allure of the money in the Ball python market is attracting everyone's attention and dollars.

John