Owning, running, and selling solar powered cryptocurrency mining gear and services.
I have a list of a dozen or so coins that should endure, so I would mine those and could provide mining for other people that want to (for a fee) mine those. I am thinking that the investment return (equivalent to yield) on mining using solar power should be excellent.
Tax lien auctions are done by county governments. You can get an annualized 16% or so, but will end up owning/reselling some properties that you obtain at way below market cost. More and more, these auctions are done online.
Do this in a county that you know or where you would like to own property. It may be possible to get the new Trump capital gain exemption by purchasing liens and hence property in the new economic development zones. Pick properties upstream of the city where affluence and prices will rise as economic activity recovers.
See the Iraq page.