Thats way too vague a question Im afraid, Some may be toxic, some may not. Try to find a species (if any) that are found in your chams natural local.
Another point is if your cham eats plants or not, if it does be very careful. Folk use them to great effect with dart frogs and the like, but they dont eat them.
Another issue is ofcourse weather your chosen brom will endure conditions in your chams enviroment.
Theres a list of safe plants on this site somewhere, a little boring perhaps but safety first.
Many bright flowering plants may look great but be toxic, or not suited to conditions in your cage and ultimately die wasting money. The ones listed here are generally very hardy, reasonably attractive and edible.
If you really like the asthetics of bright colors (chams reactions aside), find tough plastic plants from your local art shop. This can be used with great effect also.
i just might i have the one with the green/dark green stripey leaves and with the long red tips feather looking flower comingo ut of the middle. i read up on it and it said they can be found in warm rainforests so i'd imagine them to be okay *scratches head* i got a ficus too
I think you'll find that they're not toxic (they're very common in vivariums) but they need an environment that is very wet, not something easily provided for chams.
They're one of the #1 choices for Dendrobates though, the spaces where the leaves bend out from the main stem are quite water tight and work like a cup, they catch water and some species of dart frogs lay their eggs in there for the tadpoles to grow in- Quite cool actually.
They do not need a very wet environment, but they do need to be misted frequently.
Neoregalia bromeliads have a great variety and a wide availability. There are many bromeliad farms in the states you could order from. The Canadian Dart Frog Society just did a group order and it worked out to 4$ for each bromeliad after we ordered 50+, of course some of the rarer species can run 20-60$
They are not toxic, to my knowledge, but there may be some that are? I doubt it though (there are many many many species however).
They don't have very strong root systems, so they will need to be secured into your cage with wires, glue, or some makeshift hanging method.
They should never be planted in the ground, as they are meant to live epiphytically, which means they get their nutrients from the air and humidity and with spraying. You should mount them from the middle of your cage upwards.
They like lots of light, though there are many species you can get that do well in low lighting levels.
They would be great in a veiled chameleon vivarium, but they do need to be secured well so the chameleon doesn't make the plant fall off the wall/background when they crawl on it.
There are some varieties that grow very large, and those are the ones I would recommend using for chameleons.
As for coming from their natural environment, no they are found in the Americas.