A coconut would be good addition. You can find wood, coconuts, and other decor on Amazon or from reputable breeders like Pangea or Josh's Frogs, or you can look to your local pet stores or upcoming reptile expos. For example, I found this and this coconut hide(s) on Amazon for really cheap (I find that the ones branded for birds are a lot cheaper than lizard-branded ones although they're the same thing). Here's a reptile-branded digital thermometer/hygrometer with good reviews and this is one that records high/lows and can be attached magnetically or be set on the bottom of the tank (again, I prefer buying ones that aren't branded for reptiles). Reptile Expos have a lot of good discounts, I managed to find a discounted coconut hide from $10 to $5 at a reptile expo because the string untied. Also, pet stores may have discounts ever so often but I find more success shopping online as there is more variety.

REPTI ZOO Reptile Terrarium Thermometer Hygrometer Digital Display Pet Rearing Box Reptiles Tank Thermometer Hygrometer with Suction Cup https://www.amazon.com/dp/B07D284W96/ref=cm_sw_r_cp_api_glc_fabc_AE-9Fb29BMXAB

I use this one. My crabs also love to destroy things so i ziptied a string around it and ziptied the other end of the string to a suction cup and suspended it in the middle of the tank from the lid. Hasn't been destroyed since.