Useful self-hosted solutions can make great weekend projects (just saying).
This collection covers:
- Recipe management
- Gamifying productivity and habit management
- Expenditure management
- Workout manager
- Password manager
Often these solutions will run even on a Raspberry Pi connected to your network at home. They are open source, too, so there is no cost to installing or running them.
See https://www.xda-developers.com/self-hosted-apps-that-will-improve-your-life