My most used:

• self hosted Matrix server with Element client
• Jellyfin server and clients
• self hosted Radicale server for my family calendars
• self hosted Joplin server with the Joplin app on all my machines and devices for my notes
• Navidrome
• Firefox
• tasks.org with my self hosted nextcloud
• all the fossify apps on my phone
• audiobookshelf server and client
• GNU/Linux (various distros across different machines)
• Voyager for Lemmy

There's a bunch more that I can't think of that I use, but the above list is the stuff I rely on and use every day.