u/Lord-Zoinks

Hello, I hope this is the right place to ask a question like this.

I recently came into possession of a 50x25x20 cm terrarium (~20x10x8 in, ~6.6 gallons). I'll need to fix the screen lid and the rubber edge around the top, but it's otherwise in good condition. I'm aware that this size is definitely too small for any reptiles or amphibians, so I was wondering if anyone had any recommendations for invertebrates that would take well to a tank of this size. I don't have any extenuating circumstances (arachnophobia, allergies, etc.) that would cross any particular animals off my list but am not too experienced in keeping demanding inverts (I have millipedes for reference).

Thanks for any help that anyone provides!