With these smaller geckos, about the only frogs that are safe to share a tank are the smaller dart frogs, aka "thumbnails" -- but there are some beautiful frogs in that group! They eat fruit flies, so you'd have to raise those if you're not already, but it's pretty easy -- I jut buy dry media that I mix with hot water. Most dart frog places sell it. FFs are also good food for baby geckos ;-)
However, one thing I have noticed when housing frogs and geckos together is that the stress level goes up a bit, so it's not the ideal breeding situation for either species.
Melody