Communal living

[Truffs1178]

Maybe a red eyed tree frog or a male whites. A female will probably get big enough to attempt to eat the crestie. In my opinion though you should go against communal living because of spread of disease, stress on some tank mates and the fact that each animal has its own specific requirements e.g. Different temp, humidity etc

[Bolisnide]

Actually, I think you'll find that most do not recommend mixing frogs with a crestie... so many reasons.

Here's a great article about it: Amphibian Care >> Mixing Different Species of Reptiles and Amphibians Together

In my humble opinion, the answer to your question is, "no."

[Monza geckos]

Ok I was just wondering I didn't think so anyway

[Truffs1178]

I didn't think so either but if you do then don't put anything together that has different requirements or that will try to eat the other. Don't know if you read the article that Bolisnide provided the link to but I did and it basically says no unless you have the time and money.

[Lija]

Absolutely not! You can't have anyone with crested gecko, including another crested gecko. They are solitary animals, females might be housed together under very close watch, breeding pairs during breeding season if enough space is provided and if they are not fighting. But to place another species is absolutely out of question for so many reasons.
You have a male, thus he has to be housed alone. If his cage mate is another male they are gonna fight... Sometimes badly. if it is a female, you are running into big problems for both if housed together on a full time basis.

[Monza geckos]

Ok what about an insect eg stick insect thats edible if they ever did fight