Before looking for unofficial mirrors, check the . They provide real-time updates. If the site is down for everyone, a mirror might not work either, as they often pull data from the same source. Use the Wayback Machine
Occasionally, tech-savvy members of the fandom create read-only versions of popular tags or works, though these are rare due to the massive size of the AO3 database. Why Would You Need an AO3 Mirror?
AO3 Mirror: Everything You Need to Know About Accessing the Archive