https://kevincox.ca/2022/05/06/rss-feed-best-practices/

People generally call feeds "RSS Feeds" but usually they aren’t specifically talking about RSS. RSS isn’t the only, or even the best format. Using a standardized format is critical to your feed being understood by the widest variety of readers and search engines.

miniflux

A self hosted rss reading server. Integrates nicely with various native programs.

https://everest-pipkin.com/teaching/handmadeRSS

A guide to writing RSS by hand. Or at least understanding it really well.

https://vore.website

Free, simple, and plain rss aggregator.

https://github.com/piqoni/cast-text/blob/main/main.go

Has various issues, but could be used as a basis for eventually writing my own.

rssmail

Nice rss to email tool.

feedmail

Very nice but, paid, rss to email service.

greg

A command-line podcast aggregator.

castget

Automatic podcast downloader and tagger. Can be used with mpd.