Booksaregreat
Here is suggestion,mc could buy yasuri nanami eyes because he can buy anything(she is from katanagatari ) and replace his eyes,her eyes can learn anything she sees and then upgrade it to unimaginable level it is as closest to meta-learning as it can get and it should not cost too much because its just eyes,the End from medaka box should be a lot more expansive because it is meta learning,btw this is just suggestion also golden horned beast bloodlone from swallowed star mc would be able to get stronger just by eating metal amd he can even have world in his body and he can create 3 bodies from different races and then mc can use most op races like taotie,whatever race yukari is from touhou,god races from mythology,from pokemon and digimon they are races that can create and manipulate everything,also from yugioh cards like ra or slifer and many more,you can even create races.