Unique Typing
Grass/Ice
Snover and Abomasnow
This is the first main series Pokemon game that let you choose a girl character
Pokemon Crystal
This Pokemon evolves starting at level 30 if the DS or Switch is held upside-down when it levels up
Inkay into Malamar
The Iron Snake Pokemon
Steelix
Pokemon who wears a skull
And
An item that evolves Vulpix
Cubone Fire Stone
Steel/Ghost
Honedge, Doublade, and Aegislash
This Pokemon introduced in Gen 5 was the first pure flying type
Tornadus
This Pokemon evolves if it levels up while knowing the move Rollout
Lickitung into Lickilicky
The Dopey Pokemon
Slowpoke
A Key Item that allows you to fish but only can find Magikarp
And
A Pokemon known for using Harden
Old Rod Metapod
Poison/Fighting
Croagunk and Toxicroak
This is the first Pokemon to gain a new typing in a new generation.
Magnemite/Magneton
This Pokemon evolves if its traded while holding a Dragon Scale
Seadra into Kingdra
The Weed Pokemon
Oddish and Gloom
A poisonous Pokemon that has a high encounter rate in water
And
An HM move that allows you to reach the area where Lugia resides.
Tentacool Whirlpool
Dark/Ice
Sneasel/Weavile
The first ever Nuzlocke was a playthrough of this game
Pokemon Ruby
This Pokemon evolves when it levels up while there is a Remoraid in the party
Mantyke into Mantine
The Color Swap Pokemon
Kecleon
An item used to awaken Groudon
And
A grass move that drains HP
Red Orb Absorb
Ground/Psychic
Baltoy and Claydol
In "Pokemon The First Movie" this Pokemon gave Ash the invitation to visit Mewtwo's Island
Dragonite
This Pokemon evolves starting at level 50 if it is raining or foggy in the overworld
Sliggoo into Goodra
The Legendary Pokemon
Arcanine
A low power ice type attack that hits multiple targets
And
A bear pokemon native to the Kalos region
Powder Snow Pangoro