Odd one out!

[Arma]

Omanyte in the only invertebrate of those three!

Leaf Blade, Mud Bomb or Blaze Kick?

 

[PageEmp]

Leaf blade is the only one with perfect accuracy! (I guess I'll now allow moves too since it's not specified to only mons)

Torterra, Infernape, Empoleon

 

[astraling]

Torterra is the only quadruped.

Blastoise, Feraligatr, and Milotic.

 

[Arma]

Milotic is the ony one out of those three that is unable to walk =(

Zangoose, Miltank or Ursaring?

 

[faf]

Ursaring is the only one with a pre-evolved form.
Landorus, Amoonguss, Kangashkan

 

[miragespot]

Kangaskhan is not from Gen 5.

Thundurus, Zapdos, Moltres.

 

[astraling]

edit: lmao someone posted before i did

Thundurus is not part of the Legendary Bird trio (is that what they're called?).

Magnemite, Bronzong, and Togedemaru.

 

[PageEmp]

Magnemite is the only special attacker here.

Venomoth, Scizor, Steelix

 

[miragespot]

Steelix is not a bug type.

Azurill, Cleffa, Pichu

 

[CF1994]

Azurill is a Gen III Pok?mon, as opposed to the other two.

Lurantis, Vikavolt, Mudsdale

 

[Arma]

Clearly Vikavolt, as it's the only one out of those three I'm not particularly a fan of.

Toxapex, Tentacruel or Jellicent?

 

[miragespot]

Jellicent is not a Poison type

Ninetales, Rattata, Drowzee

 

[PageEmp]

Ninetales is the only fully evolved one here.

Porygon-Z, Kricketune, Alolan Dugtrio

 

[Arma]

Porygon-Z has a non-alphabetical character in its name. Also its the only genderless one, the only one of a three stage line and I'm probably overanalyzing this.

Geodude, Mr. Mime or Mismagius?

 

[CF1994]

Mismagius is not naturally native to Kanto.

Tyranitar, Gigalith, Hippowdon

 

[Arma]

Hippowdon is the only non rock typed one there.

Jangmo-o, Deino or Gible?

 

[PageEmp]

Deino doesn't reach the final form in the lvl 40s.

Gurdurr, Qwilfish, Heatran

 

[CF1994]

Heatran is a Legendary Pok?mon, unlike the other two.

Passimian, Oranguru, Infernape

 

[PageEmp]

Infernape isnt from gen7

Diglett, Ekans, Meowth

 

[CF1994]

Ekans is part of both the Field and Dragon Egg Groups, whereas the other two belong to just the Field Egg Group.

Mewtwo, Yveltal, Jirachi