@jaackf
SyncThing. It's the best sort of selfhosted program. You set it up once and then never think about it because it just keeps quietly doing what you wanted.
Wikis can be great if you've got a few folks that need to coordinate information.
An RSS reader/aggregator.
@pineapplelover
It's not as severe as the Butter Stick: https://qmk.fm/keyboards/butterstick/
@pixelprimer
@ergomechkeyboards