If interested in bigger frogs and your tank is an aquarium; you could keep a pair of African Clawed frogs. If not; then two of any of the smaller ground Toads will do fine. Also, you could keep a pair of Tomato frogs in there too.

If more into smaller guys; you could set up tank for a small colony of Bumble Bee Toads or even Mantella frogs if you are up for the challenge. Have fun and good luck !