I believe I'm at 42 Docker containers now, lol. Some of the notable ones:
Plex
Vaultwarden
Home Assistant (plus Node-RED, zwave JS, and mqtt)
NPM
Pihole
All the "arr" stuff
Nextcloud
Portainer
FreshRSS
There is a lot of support stuff too like MariaDB and orbital-sync.
I'm going to be working on Lemmy when I get back from vacation but I leave in like 2 hours so that's going to have to wait, lol.
By in large, the docker makes it stupid easy for the vast majority of my containers and portainer makes it even easier since you can manage everything through a web UI.
I don't know that it's really necessary to use both nextdns and pihole. You may look at a couple of comparisons and decide what's best for you. I just use pihole (two of them actually, one in docker and one on an actual pi).
Yes it can, though it is easier to set some things up with the built-in addons. Most addons can be set up independently as docker containers (like z2mqtt or node-red) but may require additional configuration.
Question about Vaultwarden. How does sync work? My browser extension for Bitwarden auto syncs to their server, is that possible with Vaultwarden? Or is it more for manual backup?
Is there something killer about FreshRSS that makes you host that rather than using the Nextcloud RSS reader support? I used to have TT-RSS before I dropped it and my filesyncinc stuff for Nextcloud.