I have absolutely relied on these. Besides real estate (which is a gamble, but I was buying for nongamble reasons), my most lucrative have been grants (free money for what I was doing anyway), business projects (investing $100 in my own ideas vs another business's stock), and matching grants (employer via 401k, RESP in Canada, etc). $100 in and $32k out, or a 300% match, etc.
Leveraging the above has been critical to my path (which I explore in detail in my new book, linked to below if you're interested).