Nothing fancy, actually - the typical services people who self-host use. Some were found serendipitously, then rediscovered through https://github.com/awesome-selfhosted/awesome-selfhosted or a few "Ask HN".

Home Assistant and associated services (Zigbee2MQTT mostly), -arr suite for research purposes, HedgeDoc and some other I tried, Syncthing, Borg, file transfer, Radicale, Vaultwarden (should have started with that one), a few of my own services that I shared with the world or will share someday, Minecraft(s), ... and suddenly you are at dozens :)