Here is an example. My partner and I recently bought a house that was never listed. We sent the Owner a letter and they were looking to sell. The house was half way through a renovation so it had plywood floors, some raw framing and needs partitions laid out and framed.
In the midst of planning a renovation, we decided to see if we could sell it to another investor who it might be a better fit for. We did not want to put it in the MLS because if we were unsuccessful, we would end up rehabbing it and listing it again. Buyers would be able to see the unimproved listing and we thought it might turn some of them off. Furthermore, you will now have to deal with buyers who might not know what they are getting into.
Instead we pushed out an announcement to our contact lists and a private Facebook group of investors. We had a number of showings and negotiated an all cash sale to one of these buyers.
Next week, when the sale closes, it will have been sold twice without ever having been listed.