You could have an anole colony, either brown or green. Not to up on their husbandry requirements, but they live in groups. If you wanted to co-habit crestys you would need all females and provide a few places where they can each feed so that they're not competing for the same bit of food, and provide loads of stuff to climb on. You could also get 2 female leopard geckos and same as above, provide loads of hiding spaces. You can do whatever you want, but if your gonna do it, make sure your research is spot on and that the animals come first. I know people that do co-habit crestys together and leo's together (but never a cresty and leo together!!), but this will always be a divisive topic.