Odd One Out

[TheFunnyFeraligator]

Munchlax is the only one who weighs over 200 lbs (let alone 35).

Garchomp
Salamence
Aggron

 

[Meadow]

Garchomp is the only Generation IV Pokémon. =P

Moltres, Zapdos, Articuno

 

[DyingWillFlareon]

Moltres, it is the only one who's FRLG location is different from it's RBGY location.

Chatot, Chimchar, Happini

 

[Meadow]

Wynaut is the only Generation III Pokémon.

Pikachu, Pachirisu, Dedenne

 

[Master Kavar]

dedenne because its a fairy/electric and the other two are stricly electric

Venusaur , Sceptile and Meganium

 

[TheFunnyFeraligator]

Meganium is the only one without a Mega Evolution.

Tornadus
Thundurus
Landorus

 

[Meadow]

Landorus is the only one who isn't a version-exclusive.

Rayquaza, Giratina, Kyurem

 

[classiccartoonsftw]

Kyurem doesn't have any immunities.

Pikachu, Marill, and Togepi

 

[Meadow]

Pikachu is the only Pokémon that was introduced in Generation I.

Mew, Celebi, Shaymin

 

[DyingWillFlareon]

Shaymin is the only one with two formes.

Ponyta, Piplup, Bronzor

 

[Lycanthropy]

Bronzor is the only one which name is not six letters.

Aron, Lairon, Aggron

 

[Master Kavar]

Aggron because it is on two legs Aron and lairon are on four legs
Mesprit azelf uxie

 

[Meadow]

Mespirit is the only Pokémon that roams Sinnoh.

Regirock, Regice, Registeel

 

[Lycanthropy]

Regice is the only one not learning Iron Defense.

Reshiram, Zekrom, Kyurem

 

[DyingWillFlareon]

Reshiram, its name isn't 6 letters. 8D

Munna, Tepig, Patrat

 

[Master Kavar]

Dodrio is the one who can't levitate

Pidgeot, fearow, noctowl

 

[Foamster-Whiskey]

Pidgeot is the only one with 2 pre-evolutions

Diancie Shaymin Arceus

 

[AtecainCorp.]

Ninetales. Since It was fire pokemon

Xerneas Sylveon Carbink

 

[Meadow]

Xerneas is the only legendary Pokémon.

Vaporeon, Flareon, Leafeon

 

[Foamster-Whiskey]

Leafeon is not from the first gen

Lugia Ho-oh Celebi