This is surely a Selaginella that stands out from the rest. The silvery/white foliage will almost certainly pop among the dark colors and the greens in a terrarium.

The chloroplasts are mobile, and will move throughout as the day proceeds and lighting changes. This gives rise to the white/silvery sections- I've observed fronds nearly completely devoid of white sectors during certain periods.

High humidity terrarium culture.

Non-exact, grower's choice cutting, though the photo is representative of what you can expect.