What type combination has the least weakness' and which has the most?

Question

It can be any type combo.

Comments

Are we limited to two types? I know that water ground flying steel and water bug steel dragon have no weaknesses.

Answer 1

For this list I will not be including abilities, the types listed might not exist either.

Least Weaknesses:
Normal has one
Water/Ground has one
Electric has one
Dark/Poison has one
Ghost/Dark has one
Steel/Bug has one
Normal/Ghost has one

Most Weaknesses:
Ice/Grass has 7
Psychic/Grass has 7
Psychic/Rock has 7
Grass/Dark has 7

Hope this helps!

Source1
Source2

Comments

Grass Dark has 7 aswell.

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normal ghost has one.

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Why did you list some type combinations twice?

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They aren't exactly the same, just backwards

yeah, that is kind of stupid

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Water dragon and psychic dark used to have one weakness, but those days are long gone now...

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If Foresight or Odor Sleuth is used by an opponent on someone with a GHOST/DARK Type, the opponent has Scrappy, or this Pokémon is given a Ring Target, the effectiveness of  Normal-type  moves is 1× and the effectiveness of  Fighting-type  moves is 2×.

If Miracle Eye is used by an opponent or GHOST/DARK type is given a Ring Target, the effectiveness of  Psychic-type  moves is 1×.