This weekend, I learned that Mastodon provides at least two types of feeds, your toots (Your feed URL is [instance]/users/[username].rss or .atom, for example https://mastodon.social/users/brownpau.rss), and your toots with replies (https://zirk.us/@bsigmon/with_replies.rss). In addition, there is a service called OpenRSS which can also generate RSS feeds for different Mastodon activity.