I have a pothos hanging from the frame of my enclosure with fishing line. It has grown like a beast in the last 5 months that it's been in my enclosure and has taken over. I dont even need vines or branches anymore because it has become so dense. That being said I have an 18x18x36 enclosure so 1 pothos is able to cover that sort of ground (my new custom enclosure is almost ready!!), I would suggest a few more than that for a larger enclosure. I like umbrella plants for tall sturdy plants if you're just looking for something to put on the floor of the enclosure, but good sized ones can be pretty pricey whereas you can get a pretty nicely developed pothos for like $15. I really like the texture that ferns bring to an enclosure. They dont provide much in the way of walkways but can produce a nice dense cover for your cham and they grow pretty quickly. I put a small one at the bottom of my enclosure about a month ago and the fronds have already grown up to the top of the enclosure.