There isn’t much, unfortunately. I love azou’s fics about Ye Zun, I love how she writes him. My favorite is have you looked up in the sky. It’s AU crossover with Nirvana in Fire, but you don’t have to know it to enjoy the fic IMO (I haven’t watched NIF). The fic is mostly about Ye Zun, but it has a lot of angst about his relationship with Shen Wei, which I love. She also wrote incest AU, which I liked, too, but it’s not everyone’s thing.

I Thought It Was You by spinningthreads if hilarious

Two by circumference is a very interesting look at pre-canon Ye Zun and Shen Wei

These are my favorite. Like I’ve said, not much. :)