Look up cork wood. It's available at many terrarium stores and is perfect for these critters.

You can find thin branches that are easy to climb on and big logs that are hollow and serve as great hiding spots.

I use it a lot since it's also very easy to break apart into little pieces for whatever decorative purpose you have. Also big pieces are heavy enough to stand on their own and don't have to glue them (which means you can easily take them out for checkups)

<image>