Warlock patron idea: it's literally just the dm, the dm as a person is your warlock's parton.
Bonus points if your character knows that they're just like, a regular person, but also somehow gives them magic power? For any cool warlock shit you have to appeal directly to the dm but in character, which is unreasonably meta but I love the idea of a warlock just kinda of being lick "for the love of fuck Jeff can I PLEASE have my spell slots back"