Syncthing, Plex, and DokuWiki.
My needs are small but Syncthing is for standard file sync and DokuWiki is for a repository for my family. It’s been surprisingly useful to be able to spin and delete up a syncthing folder for some specific thing.
Plex is for my ripped DVDs and also a great way to consume my photos archive without keeping a copy locally on my phone.
Upside: Easy as pie and can be used by anyone who has used Dropbox/OneDrive/GDrive/whatever
Downside: everyone gets a copy of every file regardless. Good luck getting rid of old files. Could be fine, though.