I think that rental real estate is not perfectly passive income. Landlords need to make a lot not only in order to list the property, but also to keep reliable tenants. So, I would say that it could a challenging job, for people, who have rental real estate but not a source of passive income. Maintenance and management costs that should to be also considered.
Crowdfunding is a newer way to invest, having emerged onto the scene just within the last few years. Most people have heard of sites like Kickstarter and GoFundMe, and a very similar concept exists for real estate. Developers are always looking to raise capital to fund their projects. Through the various online platforms, investors have access to these projects and can choose to invest in both residential and commercial properties. See the List of My Favorite Crowdfunding Sites. https://www.listenmoneymatters.com/wp-content/uploads/2017/08/buy-online-business.jpg
Let’s continue the vintage BMW idea. Old cars obviously require quite a lot of maintenance. Many people will buy a “fixer upper” with the intention of spending their spare time repairing and restoring it. There’s a very obvious market here: a guide to restoring different BMW models. Depending on your knowledge, you could produce detailed guides for the three or four most popular models and sell them. Not everyone restoring a car will buy them, but some probably will.
If someone stole my hard work and passed it off as their own, I’d be livid and would pursue them to the ends of the Earth for full restitution. A man I hired to work with me registered my preferred domain name of my business and has re-registered it in subsequent years. That’s bad enough; I’m mad as hell. The worst aspect of his behaviour is that I don’t know WHY he has done that; I paid him the fee we had agreed on and thanked him for his input. We also got along perfectly well during the project so far as I know, so I don’t see what his problem is.

When a taxpayer records a loss on a passive activity, only passive activity profits can have their deductions offset instead of the income as a whole. It would be considered prudent for a person to ensure all the passive activities were classified that way so they can make the most of the tax deduction. These deductions are allocated for the next tax year and are applied in a reasonable manner that takes into account the next year's earnings or losses.