I meant from your "locked out" list, there are some LOTR groups that I have attempted to join and gotten nothing back from the mods, yea or nay. Perhaps that's not what you meant! These are three that I've spotted so far: aragorn-legolas, fanfic_of_arda, lordoftheringstrilogy
The first is particularly large, tons of messages - but you can't see them unless approved as a member, alas! (Some say you need approval but as soon as you apply you can read the messages, so while I can't get files/photos from them, the messages at least can be backed up.)

I'm still working my way through every LOTR one I can find, and then I'll probably turn to X-Men. I've already gone through all the Pretender ones and all those for smaller fandoms that I could think of.