Finding consistent and high-quality fem!Ichigo content feels like a specialized hunt, partly because the concept itself attracts a certain kind of writer. While Archive of Our Own (AO3) has become the central hub for most ship-based fanfiction with robust tagging, the quality for this niche can be wildly inconsistent. You'll get a lot of half-finished AUs or stories where Ichigo's gender swap is barely explored beyond surface-level changes. I've had more luck filtering meticulously on AO3 by kudos and publication date, but honestly, a good chunk of the truly dedicated work seems to migrate to smaller, fandom-specific forums or even personal blogs that are harder to track down.
For a more curated experience, I sometimes check dedicated 'Bleach' fanfiction communities on sites like FanFiction.Net, using their community filter function. Some users there have compiled lists or created communities specifically for gender-bent 'Bleach' stories, which can act as a decent aggregator. The downside is the update frequency isn't always great, and the tagging system is prehistoric compared to AO3, making it harder to avoid things you don't want. My last find was a pretty solid slow-burn fem!Ichigo/Ulquiorra story on a now-defunct forum archive; it's a reminder that a lot of the 'best' stuff isn't always on the biggest platforms, but scattered in digital corners where the writer felt most comfortable posting.