I think h1b requires income only from the employer or from passive income. What is included in passive income? Does it includes Stock, renting out a room, renting out a car via a third party service? I'm only asking about legally renting and filing tax and everything correctly.
Ask your attorney
Passive income is okay. You can't be a Uber driver but you can rent a house or car.. confirm with an attorney though.. I don't have first hand experience in this area..
Cash only
You can earn additional income as long as you are not working for it. You can work on anything as long as you are not doing it to make money. E.g. YouTuber, blogging, book writing
In this case your car will be a property that you rent out. Which is passive income.