Yes they exist. I have a close friend that did one. The hard part is actually finding one.
In his case he had been working with a realtor for months. The realtor had a neighbor with a run-down house. The neighbor tried to sell it to a wholesaler who made a super low-ball offer which she found offensive. The neighbor contacted the realtor who called my friend.
My friend offered $10K more than the wholesaler and bought the house at about 50% of ARV less costs. Using hard money he funded purchase and rehab with $0 out of pocket. When he went to refi to a conventional mortgage he actually got a few $$ back.
That is true infinite return!
Yes they exist but you’ll likely need your purchase and rehab costs to be at most 65-70 percent ARV