such as single family homes that would be kept as rentals? I am speaking of the no money down techniques that do not involve obtaining a mortgage from an institutional lender.
how would these techniques work?

most of the TV stuff to sell you programs are garbage.

There are ways though, like 0 down loans, but those are getting harder and harder to get now.

The VA does it still if you’re a vet

you can set up an owner carry with zero down, then get a refi loan for more than the principal of that and use the balance for down payment and even pocket some, but the banks are getting tough.