Ehh just stick to insects. If you want variety why not go for the following:
Crickets
Locust
Grasshoppers
Roaches
Moths(no butterflies)
Earthworms(of all kind)
Wax worms
Pheonix worms(high in calcium)
Slugs
Snails

Etc.

Stay away from other amphibians, reptiles, fish and mammals as a food. Just trust me on that one.