You can easily disregard UEE, Prison Mod, and Endless Journey, so it's a toss between HGG and Xianxia
Xianxia has more repetition, with pretty hollow battles with no scenes just to pad things out, but that aside, does have a lot of characters. The standard of quality is very low, but I think it might have more content.
HGG is more careful about quality, so it's a better mod, but I'd hazard to guess it's not as expansive.
If you're really hungry for CoC, play both, because they also have very different content from each other.