Here are some of the things I self host that I haven’t seen mentioned:

• Continuwuity is a chat server that talks Matrix, so you can join the chat rooms of a lot of open source projects or make end to end encrypted private chats
• Forgejo is a self-hosted code forge (github alternative) - very useful
• FreshRSS is a good one if you like to follow blogs, newsletters or pretty much anything 'news’
• Grafana plus VictoriaMetrics and/or Quickwit is very useful for keeping track of the health of all your services
• Homepage is a… homepage for all your services
• Stalwart gives you a mail server. Set it up for any other projects that need to send mail, or as a backup for your emails, contacts or calendars - it’s the easiest way to set that up self hosted. Making it suitable as your main email may need more effort (delivery).
• Related to Continuwuity / matrix, you can set up the Matrix collection of bridges, which let you bridge Discord, WhatsApp, IRC, telegram, and more into your matrix account or chats seamlessly.
• LMS (lightweight Media Server, not to be confused with Logitech Media Server) is an alternative to Navidrome that I find works better with my library tagging and ListenBrainz
• Speakr - audio transcription with diarisation. Very useful if you like to record meetings.