Sites like AO3 going down can be very stressful for a lot of people. You don't want to resort to Fanfiction.net or Wattpad or Quotev and struggle to find a good fic. Here are some quick suggestions:
TV Tropes has FanficRecs pages for most works. A lot of these skew heavily towards Fanfiction.net and come with reviews and descriptions to help you gauge if they're for you. More trustworthy than FFN stats.
Fancake and Crack Van
The Fancake Dreamwidth community and the Crack Van LiveJournal community have fanfiction recs for many fandoms, sortable by tags, leaning towards older communities like FFN, LiveJournal, and Dreamwidth.
Wayback Machine
Try your links with web.archive.org/web/ at the start and see what's been saved. You'll have to wait to leave kudos or comments, but many fics are backed up. If they're multichapter, your best bet is either the full work view or to download the work, but sometimes most chapters are archived individually. You can view most tags, flip through results by year, and some filtered searches have even been saved.
SquidgeWorld
SquidgeWorld Archive uses a slightly older version of AO3's setup and hosts over 41,000 works, many backed up from older (now offline) sites. Fans of more controversial ships and somewhat older fandoms will have better luck here than modern or anti-shipper fans, but there's a good variety.
The Jinjurly Audiofic Archive has over 4,000 podfics, browsable by a number of tags, including fandom and ship. It has pretty much all the big fandoms, both modern and older (and including RPF), in the dozens or even hundreds.
YouTubers
The following YouTubers make interesting videos on fandom history: Super Eyepatch Wolf, Jenny Nicholson, Lindsay Ellis, Sarah Z, Izzzyzzz, Eldena Doubleca5t, Red Bard, biz barclay, Ashley Norton, Ana Isabel, David M, and AllironTalks. For shorter and less analytical videos, try ColeyDoesThings or STRANGE ÆONS.
Fanfiction
TV Tropes fanfiction rec lists.TV Tropes has FanficRecs pages for most works. A lot of these skew heavily towards Fanfiction.net and come with reviews and descriptions to help you gauge if they're for you. More trustworthy than FFN stats.
Fancake and Crack Van
The Fancake Dreamwidth community and the Crack Van LiveJournal community have fanfiction recs for many fandoms, sortable by tags, leaning towards older communities like FFN, LiveJournal, and Dreamwidth.
Wayback Machine
Try your links with web.archive.org/web/ at the start and see what's been saved. You'll have to wait to leave kudos or comments, but many fics are backed up. If they're multichapter, your best bet is either the full work view or to download the work, but sometimes most chapters are archived individually. You can view most tags, flip through results by year, and some filtered searches have even been saved.
SquidgeWorld
SquidgeWorld Archive uses a slightly older version of AO3's setup and hosts over 41,000 works, many backed up from older (now offline) sites. Fans of more controversial ships and somewhat older fandoms will have better luck here than modern or anti-shipper fans, but there's a good variety.
Podfic
JinjurlyThe Jinjurly Audiofic Archive has over 4,000 podfics, browsable by a number of tags, including fandom and ship. It has pretty much all the big fandoms, both modern and older (and including RPF), in the dozens or even hundreds.
Fanlore
If you're nerdier like me, you want to learn about fandom histories and drama. See the Wayback Machine heading above for a quick option (Fanlore links are formatted as fanlore.org/wiki/Title_of_Page), or look below for more engaging options.YouTubers
The following YouTubers make interesting videos on fandom history: Super Eyepatch Wolf, Jenny Nicholson, Lindsay Ellis, Sarah Z, Izzzyzzz, Eldena Doubleca5t, Red Bard, biz barclay, Ashley Norton, Ana Isabel, David M, and AllironTalks. For shorter and less analytical videos, try ColeyDoesThings or STRANGE ÆONS.