Honestly, I'm not sure there's a current, definitive 'best' list for that pairing in the way there would be for something like 'The Last of Us'. A lot of that fandom's content is older or scattered across smaller creator hubs, but I still revisit some absolute classics when the mood hits.
One that always stuck with me is 'Ghosts of Blue Hill' by Snowblind. It's a massive, abandoned post-canon AU where Zizzy is a reclusive artist and Bunny is a trauma therapist who moves in next door. The slow-burn is agonizingly good—every glance, every shared pot of tea feels charged. The prose is almost lyrical, which is rare for fics in that fandom space. It captures that melancholic, quiet energy of the original characters so well, even in a modern setting.
For something completely different, 'Circuit Breaker' takes them into a cyberpunk universe. Bunny is a rogue netrunner and Zizzy is a corporate enforcer hunting her down. The enemies-to-lovers tension is off the charts, and the action scenes are surprisingly crisp. It hasn't been updated in a while, which is a shame.
The real trick is knowing where to look now. The big archive sites are hit or miss; you'll have better luck searching specific tags on Tumblr or checking the dedicated Discord servers. There's a smaller, tight-knit group still making content, and they often reblog or link to each other's work. I found a recent one-shot on Tumblr called 'Borrowed Light' that was a quiet, domestic slice-of-life piece—just them fixing up an old cabin. It didn't try to be epic, and that's what made it perfect.
I guess my advice would be to sort by 'Date Updated' on AO3, but temper your expectations. The golden age for that ship might be past, but the stories that are there have a real, enduring charm. I keep hoping someone will drop a new longfic that blows everyone away, though.