Finding Feeds
AutoFeeds supports RSS 2.0, Atom 1.0, and JSON Feed 1.0/1.1 feeds.
Bluesky
Bluesky provides RSS feeds for user posts. All you need to do is add /rss to the end of a user’s profile link. For example, the feed for the Bluesky account ‘@vale.rocks’ is https://bsky.app/profile/vale.rocks/rss.
Reddit has very robust RSS feed functionality which can best be referenced here: https://old.reddit.com/wiki/rss
YouTube
YouTube channels have RSS feeds. They’re a tad tricky to retrieve, so it can be convenient to use a tool to fetch them. As an example, the feed for the OuterVale YouTube channel is https://www.youtube.com/feeds/videos.xml?channel_id=UC8hQBcgwkZiG-cqhE1TDvzA.
Steam
Steam games have RSS feeds for updates and news. You must add /feeds after store.steampowered.com but before /news. For example, the feed for the news page for Terraria is https://store.steampowered.com/feeds/news/app/105600,
Steam groups also have RSS feeds. You must add /rss to the end of the URL.
Tumblr
Tumblr blogs have RSS feeds for all posts. They’re found by appending /rss.
GitHub
GitHub provides an Atom feed for releases. You must append .atom to a releases page. For example, the feed for releases of the Stoat backend is https://github.com/stoatchat/stoatchat/releases.atom
Letterboxd
Letterboxd provides an Atom feed for user activities. For example, the feed for CharliXCX’s latest watches is https://letterboxd.com/itscharlibb/rss.
Behance
Behance has an RSS for users. You must add the user’s handle to the end of this URL: https://www.behance.net/feeds/user?username=.
DeviantArt
DeviantArt fully documents their RSS feeds: https://www.deviantart.com/developers/rss
Pinterest provides an RSS feed for user posts. You must add /feed.rss after their username in the URL. For example, the feed for the official Pinterest account is: https://www.pinterest.com/pinterest/feed.rss
AutoMod Blog
Like many blogs, the AutoMod blog provides feeds. The RSS feed is https://automod.vale.rocks/blog/feed.xml and the JSON Feed is https://automod.vale.rocks/blog/feed.json.
Hacker News
Hacker News has a solid variety of feeds availiable. Notable are: the front-page (https://news.ycombinator.com/rss), newest (https://news.ycombinator.com/newest.rss), Ask HN (https://news.ycombinator.com/ask.rss), and Show HN (https://news.ycombinator.com/show.rss).
You can also use external services, such as Hacker News RSS to create a wider, more tailored variety of feeds.
Lobsters
Lobsters has a feed of all stories (https://lobste.rs/rss) and all comments (https://lobste.rs/comments.rss). Specific tags also have their own feeds, for example: https://lobste.rs/t/retrocomputing.rss.
Other Sites
If you’ve gone looking and can’t find a feed for a site, look into Open RSS which goes looking for you and will generate a feed for sites that don’t have them.