Starting with the obvious, RSS feed directories can help you find popular feeds by topic. follow.it has one of the better ones, but there are others.

RSS Feed Directories often don’t keep up with the various RSS feeds provided by content producers, so you can go directly to the content producer themselves. For example, BBC publishes a list of all their RSS feeds.

Oddly enough, RSS is a great way to keep an eye on some subreddits. I’ve found that engaging in the comments of many subs is a recipe for misery, but keeping an eye on articles posted to subs really is a great way to keep up to date.

As described here you can just add .rss to any subreddit url to get an rss feed for that sub. So the CoronavirusDownunder subreddit would be https://www.reddit.com/r/CoronavirusDownunder.rss.

You can get an rss feed of commits to any GitHub repository by adding .atom to the url of a commit stream.

You might not be interested enough in any particular software project to subscribe to be notified of every little change, but there’s more to find on GitHub.

One repository I subscribe to is the selfhosted awesome list. So I get a notification whenever anything is added to this list.

There’s loads of awesome lists on github, just search for them.

There are third party rss feed generators which can scrape updates from pretty much any web page and provide it to you as an RSS feed.

Unfortunately social media platforms like youtube, facebook, and twitter don’t provide RSS feeds, so these generators are your best option.

Three of the more popular feed generation services are fivefilters, rss.app, and fetchrss. These are all freemium services.