Ball pythons and
corn snakes are rodent eaters, mice or rats are really the only feasible option for them. There are numerous good frozen feeder suppliers, all you have to do is thaw them out and shake them in front of the snake... but perhaps a snake is not a good option if feeding rodents is beyond your comfort level. Its certainly not for everyone.
There are some species, like the rough green snake, that eat crickets - but don't get nearly as large as ball pythons or corn snakes. Or perhaps a garter snake that can eat fish?
Rav