I've been using
CivGold (loads of user-made civs!) for a couple games now. After fixing a handful of files, it works, but with a few glitches, like the actual text of some civs in certain dialogues not displaying and so on. It's playable though, and with all the unique units and flags and such. I haven't had a crash yet.
When you first load the mod, write down all the files it complains about, open them up in BBEdit, go to TEXT>ZAP GREMLINS, make sure it's set to delete the characters, and ZAP, then SAVE.
This worked for me with this mod, but probably won't work for all of them. Doing this might also have contributed to some of the glitches I see, but at least it runs.
-ow