The never-ending collection of stories I've personally enjoyed about an OP MC in a variety of different situations. Usually an isekai or reincarnation.
Tends to avoid harem (or blatant romance) but there may be a few. Trigger warnings will be added. A blatantly self-indulgent list in no particular order.
Part One is here: https://www.mangago.me/home/mangalist/1132346/
Historical / Isekai / reincarnate BL I:
https://www.mangago.me/home/mangalist/835803/
Historical / Isekai / reincarnate BL II:
https://www.mangago.me/home/mangalist/1594530/
This list is for characters who have obtained supernatural abilities that help them lead better lives. They may be regressors or reincarnators but within a modern-world setting.
Edit: I have a separate list for the entertainment genre, but I've also included those who have been 'reincarnated' or granted cheat-like abilities here.