What Pokemon is the strongest on Pokemon Fire Red and Pokemon LeafGreen?

Depending on levels -

Venusuar

Charizard

War-- whatever Squrtles final evolution is

Mewtwo

Wigglytuff

Clefairys final evolution

Hypno

Next time, try to NOT delete other's answers, if you don't have a better one yourself. Here's what you should NOT delete:

(Pokemon within parentheses, (), are Pokemon who you must link with another game to get, but still works in firered and leafgreen)

Strongest Pokemon according to me based on allround stats includes:

Mewtwo

(Mew)

Any of the three starter pokemons final form: Charizard, Venusaur, Blastoise

Tyranitar

Dragonite

(Lugia)

(Ho-oh)

Gyarados

Moltres

Zapdos

Strong Pokemon in other fields (with following strenghts and weaknesses):

Chansey: (Good: lots of HP, self-generating moves. Bad: very low atk and defense)

Snorlax: (Good: much HP, pretty strong atk and spec. defense, self-generating moves. Bad: very low speed)

Steelix: (Good: defence, Bad: atk, sp.atk, sp.def, speed)

(Shuckle): (Good: Defence and Spec. Defence. Bad: everything else)

...And so on.

Please feel free to make this list longer, so that everyone who reads this answer can get some advice from it.