yes, install them all. BTS is a requirement for most, if not all, the mods out there.
oh, I forgot to mention a Romance of the Three Kingdoms mod, I didn't play it but it's supposed to be good and they added a lot of stuff to the game as well. there are also a lot of "complete", "realism", etc. mods, but I'm not really a fan of those. you can find them all at civfanatics.
Rhye's and Fall and FFH2 are the best IMO
since the game was out some modders have been trying to get a LOTR and a Star Wars mod going too, I dunno how it is. there are others that had quite some content too, but I don't know the status: an Alpha Centauri mod, Star Trek mod, Master of Orion mod. there was a cool mod called The Ancient Mediterranean, it was perfectly playable but I don't know if someone updated it to the newest patch.
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