I added rss filter/grep support to my homebrew rss->email script. So for example, I follow https://news.ycombinator.com/rss but only for articles with titles matching certain patterns:

    mike@klaus:~$ rss --list|grep ycomb
    155. https://news.ycombinator.com/rss
    mike@klaus:~$ rss --list-grep 155
    74. title = (?i)\b((e-?|web)?mail|hardenize|irc|internet relay chat|grpc|hashicorp|rust|debian|c\+\+|perl|(bit|name)coin|tor|pgp|gpg|gnupg|openpgp|digitalocean|ovh|linode|grepular|email\s*privacy\s*tester|parsemail|ssl|https|backdoor|apache|exim|distribut|peer (to|2) peer|vpn|secur|anonym|webrtc|torrent|webtorrent|nextcloud|owncloud|graphql)(ity|ous|e?s|ing?|ed?)?\b

I also randomly hit the front page of course, otherwise I wouldn't have seen this. Maybe I should add "rss" to my regex