Mastodon (microblogging social network similar to Twitter) is completely accessible -- especially once you turn on the Advanced Web Interface. If that isn't to your liking for whatever reason, Pinafore is an alternative frontend for it with even more of a focus on accessibility, and the dev is really responsive to requests. Many phone apps are also completely accessible (Android: Tusky and Fedilab, iOS: Metatext, to list just the ones that come to mind).

The community is a good one, too. I haven't seen quite so many described images anywhere else, nor as many reminders being shared to tell people who aren't adding alt text yet to do so. And it's overall a great place, at least if you like left-leaning spaces (although there are conservative instances too, they're just blocked by the rest of the Fediverse if their members are assholes). Generally the members are a part of the LGBTQIA community, artists, open source and free software lovers, scientists, furries, etc. A good number of disabled people, too.

As far as tech stuff goes: Mastodon does not track you or display any ads. There is no algorythm, everything is sorted by time, leaving you to curate your home feed for yourself. The focus isn't on visibility, popularity and enraged clicks -- indeed, there is no such thing as a retweet with a comment, only boosting the post itself, so that people are encouraged to share only what they agree with and wish to be seen. Actual human interaction and conversation are far more encouraged.

I mentioned instances earlier. This is because there is no mastodon.com, but several smaller sites that can communicate with each other. Just like how there's several email providers, and if you are on Gmail and I on Protonmail, we can still email each other. Each instance has their own code of conduct and moderators, ensuring that there are are many more moderators than on Twitter, as well as that the ones managing your community are people you know, not some faceless corporation. Which instance you join is entirely up to you, but if you'd rather not choose, I am going to recommend the one I help moderate myself, since I am biased:
https://dragonscave.space

There's quite a few blind people on it already, although it is not a blind-only community. We're still quite small, and the vibe is relaxed and welcoming. If you decide to join us though, please read the rules first, and prove that in your application by including the password at the end. If your application is lazy, it will be rejected; we get far too many bots these days.

Edit: No really, I mean it. Read the rules before applying, and include the password to prove as much. They are not long, they are not complex, but they must be read.

I use tumblr in the year of our lord 2022. A lot of people put image IDs and alt text, especially for art and memes. Its also one of the few social medias where advertising on there actually loses the company money (wheeze) so what few ads you do get are absolutely wild. (I’m thinking about the baby yoda Florida vacation home one right now.)

its also completely anonymous. If you don’t want any ads at all, pay $5 a month. Want to make your own post and have 100,000 people see it? Pay like $25. And it can be anything. I recently saw a “blazed” post (that’s what they’re called) of someone’s cat. 10/10 an amazing tabby.

Its also not ONLY pictures. You can even filter to see only text posts in the search!

It’s still very much so one of the last places of the “old” internet.

Otherwise, I’d suggest forums! Theres still plenty of them out there and they’re mainly text based.

Unfortunately most of those sights are not that accessible. Some are more and some are less of course. And a lot of the sight owners don’t particularly care to make it accessible honestly. At least the ones I’ve been on.