Contrary to above, yucca are poor choices, either true yucca or the Draceana commonly sold as yucca. They are dangerously sharp, require a good deal of light, and don't offer lateral branches or much benefit to the chameleons. Hibiscus is not a dangerous choice, but they also need full sun conditions and most find them hard to keep healthy long term.
Use ficus, Schefflera, pothos, miracle fruit trees, appropriate palms ( rhapis, cataractum, bamboo, parlor, and a few others ), aralias, and cinnamon trees for the cage. Most of those can be found online or in garden centers and are suited to chameleons and their habitats. The safe list suggest plants that are not toxic, they do not indicate the plant is suitable for use in chameleon habitats, as many are either impractical or won't survive in chameleon cages.