openRSS

 openRSS  is a website run by the OpenRSS foundation providing RSS content for all websites with dynamic content even if there is no RSS feed to surface including YouTube, Twitter, Mastodon, and more. Their mission exists so that RSS feeds can continue to be a reliable way for internet users to stay up to date with content throughout the web.

How to use
Simply input a website into the search tool in the middle of the page found at http://openrss.org. If compatible, there will be a resultant RSS feed URL that will show in its place, either being the actual feed from the originating website, or a generated one that utilizes OpenRSS's feed generators.

Example Uses

 * https://openrss.org/indieweb.social/public/local - The local timeline feed of the Indieweb.Social Mastodon instance.
 * https://openrss.org/mastodon.cloud/tags/indieweb - An RSS feed for the #indieweb hashtag as seen on that instance