Usually these mixes are extremely rare and expensive. I think the most common hybrid is the bateater, which is a cross between a retic and a burm. Ive heard of burm x ball mixes, but have never seen a burm x retic. Likely it would be sterile. People are always trying to stay ahead of the breeding curve and make something unique.
But not ball python and retics...?
1.1 Mojave
0.1 Super Pastel Congo
0.1 Pastel Het. Pied
1.0 Nuclear
1.0 Pied
1.1 Spider
1.0 Spinnerblast
1.0 Calico Ringer
0.1 Fire
0.1 Pinstripe
0.1 Black Pastel