Some RSS feeds are fantastic but far too noisy to add to most RSS readers directly. Without serious filtering, you'd get swamped with more posts than you could possibly read, while missing the hidden gems.
I built Scour specifically because I wanted to find the great articles I was missing in noisy feeds like these, without feeling like I was drowning in unread posts. If you want to try it, you can add all of these sources in one click. But these feeds are worth knowing about regardless of what reader you use.
Hacker News Newest
Feed: https://hnrss.org/newest
Thousands of posts are submitted to Hacker News each week. While the front page gives a sense of what matches the tech zeitgeist, there are plenty of interesting posts that get buried simply because of the randomness of who happens to be reading the Newest page and voting in the ~20 minutes after posts are submitted. (You can try searching posts that were submitted but never made the front page in this demo I built into the Scour docs.)
Pinboard Recent
Pinboard describes itself as "Social Bookmarking for Introverts". The recent page is a delightfully random collection of everything one of the 30,000+ users has bookmarked. Human curated, without curation actually being the goal.
Bearblog Most Recent
Bear is "A privacy-first, no-nonsense, super-fast blogging platform". This post is published on it, and I'm a big fan. The Discovery feed gives a snapshot of blogs that users have upvoted on the platform. But, even better than that, the Most Recent feed gives you every post published on it. There are lots of great articles, and plenty of blogs that are just getting started.
Feedle All
Feed: https://feedle.world/rss
Feedle is a search engine for blogs and podcasts. You can search for words or phrases among their curated collection of blogs, and every search can become an RSS feed. An empty search will give you a feed of every post published by any one of their blogs.
Kagi Small Web
Kagi, the search engine, maintains an open source list of around 30,000 "small web" websites that are personal and non-commercial sites. Their Small Web browser lets you browse random posts one at a time. The RSS feed gives you every post published by any one of those websites.
Thread Reader
Thread Reader is a Twitter/X bot that lets users "unroll" threads into an easier-to-read format. While getting RSS feeds out of Twitter/X content is notoriously difficult, Thread Reader provides an RSS feed of all threads that users have used them to unroll. Like the content on that platform, the threads are very hit-or-miss, but there are some gems in there.
Minifeed Global
Not an RSS feed: https://minifeed.net/global
Minifeed is a nice "curated blog reader and search engine". They have a Global page that shows every post published by one of the blogs they've indexed. While this isn't technically an RSS feed, I thought it deserved a mention.
Note that Scour can add some websites that don't have RSS feeds. It treats pages with repeated structures that look like blogs (e.g. they have links, titles, and publish dates) as if they were RSS feeds. Minifeed's Global view is one such page, so you can also get every post published from any one of their collected blogs.
Update: since writing this post, Minifeed added an RSS feed for their global feed: https://minifeed.net/global/rss.xml.
arXiv
Feeds galore: https://info.arxiv.org/help/rss.html
arXiv has preprint academic articles for technical fields ranging from Computer Science and Mathematics to Physics and Quantitative Biology. Like many of the feeds listed above, most of the categories are very noisy. But, if you're into reading academic articles, there is also plenty of great new research hidden in the noise. Every field and sub-field has its own RSS feed. (You can browse them and subscribe on Scour here).
While reading my Scour feed, I'll often check which feeds an article I liked came from (see what this looks like here), and I'm especially delighted when it comes from some source I had no idea existed.
These types of noisy feeds are great ways of discovering new content and new blogs, but you definitely need some good filters to make use of them. I hope you'll give Scour a try!
P.S. Scour makes all of the feeds it creates consumable as RSS/Atom/JSON feeds, so you can add your personalized feed or each of your interests-specific feeds to your favorite feed reader. Read more in this guide for RSS users.