I have a slightly older relative I recently helped move, and we got to talking about investments, real estate in particular. She's smart enough, and we both feel comfortable sharing experiences and financial details.
A few decades past, she and first husband had a house in an HCOL area of Southern California that had a big run-up in value. Thyey cashed out some equity and put what seemed like $50,000 toward a deal some friends were putting together to purchase a non-descript apartment complex in the Inland Empire. Like, one of the dullest deals you could imagine. I've seen the property. It's home to hard working and retired people who are solid and for the most part, pay their rent on time.
Relative has had this property for 30 or so years, and pulls in $1800 per month, with basically zero output. A few meetings a year. This may or may not be a unicorn situation. Look around us: apartment complexes, strip malls, and the like. An REIT is even easier but possibly not as lucrative.