all time favorites

[aqrar]

Who’s the strongest anime character of all time?

 

[Halo]

Since you didn't define the type of strength you're talking about, this guy:

 

[Teddy]

Clearly Didn't

 

[BroederTrapist]

It depends what one means by "Strongest".

But King of All from Dragon Ball Super should be mentioned.

Whis states that nobody in this world is greater than Zeno, as the King of All has the power to instantly wipe out anything (or everything) in the blink of an eye without any effort, including individual people, planets, galaxies, and even universes. If he so wished, he could erase all existence, which Future Zeno did during "Future" Trunks Saga. According to Whis, there were originally 18 universes before Zeno destroyed 6 of them when he was in an "unpleasant mood".