The most weaknesses that a Pokemon can have is 7 weaknesses.
The Pokémon types that have 7 weaknesses include:
Solrock and Lunatone are the only Psychic/Rock types but they are spared as they have the Levitate ability, removing the Ground weakness.
Exeggcute, Exeggutor and Celebi as Psychic/Grass types, Snover and Abomasnow as Ice/Grass types, Nuzleaf, Shiftry and Cacturne as Grass/Dark types, Terrakion as the only Fighting/Rock type, and Tyranitar and Mega Tyranitar as Rock/Dark types have the most weaknesses out of all Pokemon.
The most resistances a Pokemon can have is 11 resistances.
This is only the Steel/Electric type, which belongs to Magnemite, Magneton and Magnezone.
Eelektross only has a Ground weakness which is negated with it's Levitate ability, meaning it's the only Pokemon that has no weaknesses. All pure Normal-type Pokemon have no resistances, but rather have neutral damage from everything except the Fighting-type.
Hope I helped. :)
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