12x12x12 Exo Terra

I recently came into possession of a 12x12x12 Exo Terra cube and have been trying to figure out what, if anything, can live comfortably in this size terrarium. I've read pictus, viper, and mourning geckos could live in it, as well as pacman frogs and smaller newts but I've also read that none of those will be ok long term in that terrarium so I'm trying to figure out what I can actually do with this tank or if its just a waste of space

I have a pacman frog in one now and it's a little bigger than a golf ball. It doesn't really use much of the enclosure except a 6" diameter. I think they would work great with a few spiders or a small planted setup. I got this exo from my brother who got it from someone that had a crested in it. I'm not sure if it was appropriately sized for long term housing but the gecko was small.

A crested wouldn't do well in this size tank long term, I actually used it as a temporary home for one of my females when she was too small to be housed with my larger girl. I think I'm leaning towards a pacman because I know the males stay smaller and might be ok in the tank permanently and if he outgrows it I can always upgrade him to a larger tank

Viper gecko if you can find one!

Dare I say, perhaps a tarantula or millipede?  I have absolutely no knowledge of keeping either as pets, but I'm just putting that out there.

Or a mantis.  I'm thinking of invertebrates that I saw at the NN show...

viper geckos those guys are boss:)

As a gecko breeder, I would find it very useful for juvenile geckos. They would have to be upgraded eventually, but I constantly have different ages and sizes that would fit in a cube like that.

If you are looking for something long term, I would suggest a tarantula.

I think I might end up with a tarantula in it eventually. For the time being I have a tiny pacman in it until he starts getting too big for it.