There are techniques with better payoff and retention. Check the memory systems advocated by David Roth or Harry Lorayne, or the locus method (https://en.m.wikipedia.org/wiki/Method_of_loci)
Seconding this recommendation -- this book was a really fun (and fast!) read and was really eye-opening about how real memory tricks work and started to get me thinking about the utility of having vast amounts of information memorized.
I don't have any studies, but check the wikipedia page for examples of Memory Championship winners using the method to, for example, memorize a deck of shuffled cards or a random sequence of digits. I bet Moonwalking with Einstein would have some references in the scientific literature.
The issue with the methods is that you have to use them actively. As the author's mentor says in the book: most of the memory champions have horrible memory in normal situations, they were just desperate to change that, so they pursued mnemonic techniques. You might have an elaborate system to remember hundreds of playing cards in a loci palace (which takes months and lots of repetition to develop!!) and still frequently lose your key or forget names.
You can develop/discover and consciously apply mnemonic techniques for each situation (eg remembering names at a party by associating the name with prominent features of the face or funny analogies) but if you don't use them they'll be of little help.
Bill Clinton (or was it JFK??) is said to have all his life kept a notebook with him and scribbled down any personal facts revealed in a situation - name, alma mater, etc - and was then able to recall them when meeting the same person years later. He must have had an impressive system and much dedication - but also must have been a bit awkward to talk to when everything you say is recorded (apparently a good listener though).