Well, both me and Brian already pointed out the problem. Many plants are only dangerous when digested (since the sap is dangerous) (and therefore very dangerous to some animals, while perfectly fine for others, pothos being a good example), so you often have to make some research yourself. First of all, if you find a plant that you like, just google it. Wikipedia often have information about it's toxicity (if there is any). After that, just lurk in forums and if needed, ask questions if other people have used it, know anything about it etc. Common sense is also a good thing to use! For example, you might not want to use a dieffenbachia if you feed a big White's by putting crickets on small dieffenbachia leaves.