I keep seeing the same few tropes when I browse for Xianyun/Cloud Retainer and Zhongli fics, and honestly? They've gotten a little predictable. A huge chunk is post-Lantern Rite 'what if' scenarios—like, Zhongli decides to visit the adeptus for tea after the festivities, and one thing leads to another amid all that quiet, misty mountain atmosphere. It's cozy, sure, but after the tenth version it blurs together.
There's also a weird amount of 'modern AU with a twist' where he's a university archaeology professor and she's a brilliant but reclusive tech CEO or something. They meet at a conference. I think writers lean into that because it mirrors their canon dynamic of ancient wisdom meeting inventive, forward-thinking genius, but in a setting where the baggage of godhood is removed. It can work, but it often ends up feeling less like them and more like generic smart-people romance.
What I wish I saw more of is fics that really dig into the pre-Archon War era. We get hints of their shared history, but not much. Exploring their first meeting, or a conflict during the war where their philosophies clashed before settling into mutual respect, could be so much more interesting than another domestic fluff piece. The tension there is way more compelling than just 'will they hold hands over osmanthus wine?'
I did stumble across one once where Cloud Retainer builds a mechanical prototype that accidentally taps into the latent energy of Rex Lapis's old stone spears, and he has to help her contain it. That kind of thing—where their specific powers and domains interact in a plot-driven way—is a gem in the rough.