Some ideas are Danny Phantom X Ghostbusters
Dragon Ball viewing other timelines
A tournament of power between different type of anime and shows
Becoming a god in danmachi
A person that has a weapon or abilities to kill immortals going through the Multiverse killing all the evil immortals and gods
In to be hero x as Shazam
Being Ash Shinigami in Shaman King
In fairy tail with anti magic
In race zero but having the ability to see the future and different possibilities instead of him going back in time, he's gonna see multiple different types of possible features and he has to pick up best one A possible disadvantage of this is the if he gets the wrong fate or there's no possibility to happen that then he will have to suffer one of the futures that are bad
More…. Later If you have a idea and you don't wanna make a book about it, you can put your ideas here with your name. I'm gonna put it down so if somebody wants your idea, I'm gonna tell you and it will have your name on it.