1. Investing in dividend stocks
2. Investing in index funds
3. Creating an online course
4. Writing an ebook
5. Starting a YouTube channel
6. Creating a podcast
7. Investing in rental real estate
8. Crowdfunding real estate investments
9. Starting a blog
10. Investing in peer-to-peer lending
11. Creating a mobile app
12. Creating a software product
13. Investing in cryptocurrency
14. Starting a vending machine business
15. Investing in a vending machine franchise
16. Renting out storage space
17. Renting out parking spaces
18. Investing in a rental car business
19. Investing in a franchise
20. Creating a membership site