Jellyfin: An unfederated alternative to Plex, with some pros and cons. Very lightweight, customizable with plugins. Decent iOS and tvOS client from the devs.
I've considered Airsonic but I haven't found a good client that looks good and doesn't behave weirdly. I had one launch about 500 threads trying to transcode the same song which ate up my CPU time on my server resulting in a stern e-mailing from my host.
The Lounge - got like 7 people using it basically daily to chat
Lemmy, even though I'm the only one really actively using it.
E-Mail server, I don't get a whole lot of mail but it's a pretty important one!
Everything else tends to be a lot more idle, but I've also got NextCloud, an IRC server, soon a Matrix server, an internal VPN so all my devices can always talk to eachother no matter where they are.
It's been set up for almost a decade at this point, it's shockingly low maintenance once it's all set up and going. It is a pain to figure out Postfix's and Dovecot's fairly arcane configuration files, but smooth sailing afterwards. It's been a long time since I've even got a mail rejected/not make it to the recipient's inbox.
If you take a look at his forums, you'll see when people request features, or just ask how to set something up, his responses are usually demeaning or meant to put the person down. And a bunch of users there defend or support it. It just leaves a bad taste in your mouth.
I dunno, it might have changed recently, but I doubt it. The app itself, if you ignore the forums is pretty solid. But it was enough to look for another dev, and the one who does FreshRSS is pretty cool, and the posts just seem to load faster through FeedMe (android app)
There are multiple ways to evaluate usage. I’ll go with what I would guess is your desired measurement, things that I use intentionally (as opposed to things like dns, which just happen incidentally to other things or automation based things which are continuously running but not necessarily interacted with):
Mastodon
An app I’ve written to collect personal data
Jellyfin
Lemmy
Bitwarden (I pay to self-host as opposed to vaultwarden as the latter probably won’t have a security audit)
Plex, PiHole, Photoprism, Home Assistant, Syncthing in a hub and spoke config, Caddy for reverse proxy, custom containers for: yt-dlp, restic, and rsync.
My guess would be that each of their devices (phone, laptop, etc) syncs back to their server/NAS, but they do not sync to each other. The server/NAS is the hub, and each device is a spoke.
I liked Audiobookshelf but the RSS feed kept breaking for me. I’d pull new podcast episodes for several days then it would fail and I’d have to recreate the feed. I wonder if they’ve fixed that yet.
Never noticed anything in the last couple of weeks. I had one podcast missing new episodes because the schedule was turned off. But I might not have had it turned on in the first place.
Like most, Plex and the *arrs are the main ones, paired with overseerr
Others I use daily or frequently are:
Benotes for bookmarks and quickly saving links for later
Gotify so I have push notifications of anything that happens on the server
Koillection as an inventory of all my knitting and crochet digital patterns
Homepage this one is always a pinned tab on any browser and a shortcut on my phone, quick glance of my services with the widgets and just a click away from them.
Also hosting a minecraft instance with backups but so far no dashboard or anything
I don't see Docspell mentioned anywhere, but it's really cool document management system. Similar to Paperless, but with pretty easy way to extend functionality via addons if you need to add some extra automation when ingesting the documents.
Using 'hours of use' as the metric, it would be Plex. The ones I use every day are Libreddit, TT-RSS, Huginn and Reddit-RSS - and my own journalling app and pocket clone.