Looking for a novel where the Main Character has a power like Reigan Shen's or Gilgamesh

Hello! This is my first post, but I was really curious if anyone knew of any novel where the main character has a power like Reigan's King's Key from Cradle or Gate of Babylon from Fate. I just found the idea of a progression fantasy, where the mc starts at the bottom, would be interesting, because those abilities are borderline useless if you don't have a massive amount of treasures, and I would really enjoy to read how the mc grows until the ability actually becomes strong. If there is nothing, I might try writting one myself