While back there was one of these heavy instagram ad campaigns going around for a blind fastener system that used a mortised plate with wedge/keyholed slots and you ran a pan head screw in the mating part and they wedged together. They had several different sizes. Ive been searching high and low clearly with poor googleology wondered if anyone knew of them. Its not like a highpoint bed rail fastener but similar. Mortised plate, and the other member just gets the screws.
Thanks if anyone knows/remembers these. May have been a flash in the pan and kaput... have an application where these would be really handy.