Question

Alrounded that is. Not just Atk

Comments

I dont think he will be the stongest ever but he is the strongest right now

Answer 1

Statwise, yes. Slakings monstrous 670 base stat is higher than many legendaries and its movepool is both diverse and intimidating. However, Slaking suffer from its ability, Truant. Since it can only attack every second turn, it's stats is effectively halved to 335. It is also easily countered, being completely walled by Protect, and being setup fodder for Sword Dance and Subsitute for example.
Slaking Is not the strongest non legendary Pokemon ever.

Answer 2

Rampardos currently has the highest Attack stat of all non-legendary Pokémon with 165.

Source

Slaking's attack stat is 160.

Serebii list by attack stat

However, Slaking has the highest base total of any non-legendary Pokemon.

Serebii list by base stat

Comments

You didn't give an answer.

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... yes I did. Rampardos is the strongest non-legendary Pokemon by attack stat.

Slaking is the strongest non-legendary Pokemon by base stat.

I didn't know which stat the question was referring to, so I gave both.

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sorry,you don't answer my question

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Okay, I don't know if I can't write or something, but I did answer your question.

Rampardos is the strongest non-leg Pokemon by attack stat, Slaking is the strongest non-leg Pokemon by base stat.

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cmon guys the question was not so clear. I edited the question now. Please remove the votes.