That is some kind of hybrid with Echeveria being one parent. I'm surprised it's doing so well in low light - they like bright light, and it would actually look better, than it already does. It will flower eventually also - usually a cool reddish/pinkish clump on top of a tall stalk. And no, it would not make for a good terrarium plant, as they are succulents.
I'm assuming you're talking about dart frog terr's, which must be moist - but to answer your question - most succulents and cacti need it dry - but there are a few jungle cacti / succulents that can do okay with moisture - namely a few epiphytic ones.
That's because it isn't. It is a hybrid, with Echeveria as one of the parents. I have seen these before, but the other parent escapes my memory at the moment.
It depends on what kind of lizard you are keeping - some lizards would ruin the plant. It also depends on what kind of gecko - some geckos like it dry, others like it moist.
As before, there are plants for both situations that are succulents. Good luck!