• Youtube channels that I'm interested in, so that I don't have to use my Youtube account or the app, and just open the links via Invidious (Invidious offers their own RSS feeds, as well, but since the instances can be a bit finicky from time to time, I feel like that's the safer approach)
• World News and Europe feeds from BBC, Deutsche Welle and Reuters
• https://restofworld.org/
• 404 Media and The Verge
• GamingOnLinux, Steam Deck HQ and Boiling Steam for gaming things
• updates on some software that I use - CalyxOS and LineageOS blogs, KOReader's Github releases since my Kindle stays offline 99% of the time, modified port of Google Camera that I use on my phone
• a few TikTok people whose videos I then open through https://offtiktok.com
• release updates from the artists I'm interested in (currently Spotify-based, but I'm in the process of moving those to Music Butler)
• https://reasonstobecheerful.world because I need to know how reintroducing beavers to London has improved everything
• several webcomics, Tumblr blogs, and one newsletter from the Nazi-hugging newsletter place
• http://miniature-calendar.com/

several of those are possible thanks to RSS Bridge which adds RSS feeds for websites that don't offer it by default or offers improved versions.

Cory Doctorow's Pluralistic blog:

https://pluralistic.net/feed/

The American Prospect:

https://prospect.org/feed/?partner-feed=main-feed

The Guardian:

https://www.theguardian.com/world/rss

You can get RSS feeds of any of the Guardian sections (US, World, Science, etc) just by adding "/rss" to the http address.

Lemmy communities have RSS feeds