Iceberg lettuce is the main lettuce to avoid. No real nutritional value, just water. I remember hearing something about Red Lead a few years ago but I can't remember if it was good or bad. When I was in Australia I went to a local reptile specialized pet store for all my queries about my blue tongue skink and general husbandry of reptiles. This is a link to their bearded dragon dietary guide:

http://www.canberraexotics.com.au/showareainfo.toy?animalnid=109022&infonid=226249

This Menu covers a WIDE range that works. While it may be difficult to feed it everything that it says, its a general guide that I go by for "safe" and "not safe." I hope it helps answer your question...if it goes through. If not just reply and I'll copy over a list.