Gens I - IV
Gen IV
Ground/Flying Type
Can learn Earthquake
Two-stage Evolutionary Line
Gliscor
Gen VI
Pure Fairy Type
Has two forms
Version Exclusive
Xerneas
Gen IV Dex Entry
"It is said to have emerged from an egg in a place where there was nothing, then shaped the world."
Arceus
Gen I
Pure Fire Type in Base Form, Psychic/Fairy in Galarian Form
Cannot change forms
Two-stage Evolution Line
Rapidash
This Pokemon can Time Travel, and is shown to do so in the Anime Continuity
Celebi
Introduced in Gen II as a baby, given an evolution in Gen IV
Normal/Flying Type until Gen VI, where it gains the dual Fairy/Flying Type
Three-stage Evolutionary Line, NOT through Level-up Method
Can learn Air Cutter
Togekiss
Gen V
Pure Fighting Type
Three-stage Evolution Line, not all of them being Level-up Method
505 BST
Conkeldurr
Gen VII Dex Entry
"Revered long ago for its capacity to create iron from nothing, for some reason it has come back to life after 3,000 years."
Melmetal
Gen IV
Dual Ghost/Dragon Type
Has two forms, needs item to switch
Features in two games explicitly
Giratina
This Pokemon grants wishes every 1000 years
Jirachi
Gen III
Pure Psychic
Not found in main Region
Has 4 different forms, including its base original
Deoxys
Form of a Gen I Pokemon, introduced in Gen VII
Fire/Ghost Type
Original Pokemon can be obtained in Gen VII through almost every game
Only evolves at night
Alolan Marowak
Gen IV Dex Entry
"It uses unique fighting moves with fire on its hands and feet. It will take on any opponent."
Infernape
Gen VIII
Dual Fairy/Steel Type in this form
Has two forms, needs item to switch
Associated with a sword
Zacian - Crowned Sword
Descending from the heavens, this Pokemon halted a conflict between two others that would've resulted in the destruction of a particularly water-based region.
Rayquaza
Introduced in Gen II, given an evolution in Gen IV
Secondary Type is Flying
Two-stage Evolution Line
Dex Entry: "It can hover in one spot by flapping its wings at high speed. It flits about to guard its territory."
Yanmega
Gen VII
Fighting/Poison Type
New Evolutionary Stage of Old Pokemon
Can have Pressure
Gen IV Dex Entry
"Its programming was modified to enable work in alien dimensions. It did not work as planned."
Porygon-Z
Introduced in Gen I, given an evolution in Gen II
Dual Poison/Flying type
Three-stage Evolution Line, one through Level-up Method
Never changes typing throughout Evolutions
The personification of an opposing side, this Pokemon will bring destruction and death once it meets its own demise.
Yveltal
Gen I
Pure Normal Type in base form
Has 4 different forms, 3 of which were given in later Generations
Safari Zone
Tauros
Gen IX
Secondary type is Ghost
Three-Stage Evolution Line
Gender is statistically more likely to be Male
Skeledirge
Gen III Dex Entry
"It sharply senses even subtle changes in the sky and the land to predict natural disasters. It is a long-lived Pokémon that has a life-span of 100 years."
Absol
Gen V
Dual Grass/Fighting Type
Has a related Pokemon in future Generation
580 BST
Virizion
Capable of fusion with two other Pokemon, it waits for worthy trainers to fill its missing parts with truths and ideals.
Kyurem