i am a big fan of ficus benjamina and schefflera aboricola. you can find them at great prices for trees, they are great for foliage, and are strong. though some may beg to differ about scheffleras, if grown right, their stems can become strong enough to hold chams. my veiled and fischers love them.
as stated before too, hibiscus and pothos are great too. FlChams.com has a safe plant list database with tons of species able to go in cham enclosures. advise though, that if eaten in large amounts, some plants may be more toxic than others. all plants have a toxicity level, which is why plant switch ups are a must of you have a chameleon who is a big plant eater.