Not a new concept but i cant find more

Try isekaitrash’s list
http://www.mangago.zone/home/mangalist/840779/

These are all the yaoi/shounen Ai that are reincarnated themed that I have: one upon a fairy tale, Feng Yu Jiu Tian, Reincarnated into Demon King Evelogia's World, I think that’s probably in order of my least to most fave of the three.

There’s also an absolute star called something like The mild nobles vacation, they insist that it has ZERO romance between the two characters but....
Anyway it’s the best so you should definitely try it

Hope this helps xx

Thanks :D