theSLAYER

A Pokemon that has never been seen in the wild. With its lightning fast volleys, it can even punch through a concrete wall in the same way as a drill.
 
 Species   Hitmonchan   Nickname   (default, save lang)   OT   (recipient)   TID   (recipient)   Distribution   Saffron Fighting Dojo   Location   the Kanto region   Dates   (Various)   PID   Chance of Shiny   Games   VC RBY    Lv. 30                                                                  Nature   Random   Ability   Inner Focus (HA)   Item   None   Bundled Item   None 
    Moves   (ITALIC means Relearnable)   Comet Punch   Agility   (None)   (None) Details above depicts one caught by a player, not fully representative of this file.
If transferred from VC GS, it'll instead state the Johto Region.

After clearing the Fighting Dojo in Saffron City, the player would be given a choice to obtain Hitmonlee or Hitmonchan.

A Pokemon that has never been seen in the wild. With its springlike legs, it is able to run smoothly with long strides.
 
 Species   Hitmonlee   Nickname   (default, save lang)   OT   (recipient)   TID   (recipient)   Distribution   Saffron Fighting Dojo   Location   the Kanto region   Dates   (Various)   PID   Chance of Shiny   Games   VC RBY    Lv. 30                                                                  Nature   Random   Ability   Unburden (HA)   Item   None   Bundled Item   None 
    Moves   (ITALIC means Relearnable)   Double Kick   Meditate   (None)   (None) Details above depicts one caught by a player, not fully representative of this file.
If transferred from VC GS, it'll instead state the Johto Region.

After clearing the Fighting Dojo in Saffron City, the player would be given a choice to obtain Hitmonlee or Hitmonchan.

An original tool made by @Kaphotics

This gift was distributed randomly out of all the then possible Eeveelutions,
to players who purchased Shany's Pokémon Bread throughout April 2011.
     Species   Flareon   Nickname   (default, in )   OT   (recipient)   TID   (recipient)   Distribution   Pokémon Global Link   Location   Entree Forest   Dates   May 18 to Aug 31, 2011   PID   Cannot Be Shiny   Games   BW                                                                Lv. 10    Nature   Random   Ability   Guts (HA)   Item   None    Moves       Tail Whip   Tackle   Helping Hand   Sand Attack

   (no ribbons) Format Ver.1.0.6-3, Post Updated Date:20190105_2342

In Pokemon Diamond, Pearl and Platinum Versions, holds the event locations Seabreak Path and Flower Paradise.
After using the event item Oak's Letter, Route 224 gains an extension (Seabreak Path) which will lead the player to Flower Paradise.
There, players will be able to challenge (and potentially capture) a level 30 wild Shaymin.
The Oak's Letter event key item was only distributed to Pokemon Platinum.
     Species   Shaymin   Nickname   (default, save lang)   OT   (recipient)   TID   (recipient)   Distribution   In-Game Encounter   Location   Flower Paradise   Dates   (Various Dates)   PID   Chance of Shiny   Games   Platinum                                                                Lv. 30    Nature   Random   Ability   Natural Cure   Item   None    Moves       Growth   Magical Leaf   Leech Seed   Synthesis
  Format Ver.1.0.6-2, Post Updated Date:20180508_0038

A Pokémon that was resurrected from the genes of an ancient dinosaur. With sharp fangs, it is very vicious.
In Pokémon FireRed & LeafGreen, the player gets the Old Amber from the Pewter City Museum, via the back exit (Cut needed).
The player may then bring the fossil to the Cinnabar Island's Lab to get it revived.

It was revived from an ancient fossil. This calm Pokémon lived in a cold land where there were no violent predators like Tyrantrum.
Fossils can be revived at the Ambrette Fossil Lab by the player.

A Pokémon ancestor that was reanimated from a fossil. It lived in the sea and hunted with claws.
In Pokémon Ruby, Sapphire & Emerald, the player gets to choose between the Claw Fossil and Root Fossil during the game's narrative Route 111RS/Mirage TowerE.
In Pokémon Emerald, the player is able to obtain the Fossil that wasn't chosen in the post game.
The player may then choose to bring the fossil to the Devon Corporation at Rustboro City.

It was revived from an ancient fossil. Not able to fly, it lived in treetops and hopped from one branch to another.
Fossils can be revived at the Nacrene Museum by the player.

It was generated from a fossil dug out of a layer of clay that was older than anyone knows. It has a skull as hard as iron.
Fossils can be revived at the Oreburgh Mining Museum after the player visited the Sinnoh Underground at least once.

A Pokémon that was resurrected from a fossil found in an ancient seabed. Unable to right itself if it is flipped over.
In Pokémon FireRed & LeafGreen, the player gets to choose between the Helix Fossil and Dome Fossil during the game's narrative at Mt. Moon.
This Pokémon is revived from the chosen fossil.

It lived on the seafloor 100 million years ago and was reanimated scientifically.
In Pokémon Ruby, Sapphire & Emerald, the player gets to choose between the Claw Fossil and Root Fossil during the game's narrative Route 111RS/Mirage TowerE.
In Pokémon Emerald, the player is able to obtain the Fossil that wasn't chosen in the post game.
The player may then choose to bring the fossil to the Devon Corporation at Rustboro City.

A prehistoric and long-extinct Pokémon that was resurrected from a fossil. Swims by twisting its 10 tentacles about.
In Pokémon FireRed & LeafGreen, the player gets to choose between the Helix Fossil and Dome Fossil during the game's narrative at Mt. Moon.
This Pokémon is revived from the chosen fossil.

It was generated from a fossil dug out of a layer of clay that was older than anyone knows. It has a sturdy face.
Fossils can be revived at the Oreburgh Mining Museum after the player visited the Sinnoh Underground at least once.

This Pokémon was restored from a fossil. It swam skillfully and dove to depths beyond half a mile.
Fossils can be revived at the Nacrene Museum by the player.

It was revived from an ancient fossil. If something happens that it doesn't like, it throws a tantrum and runs wild.
Fossils can be revived at the Ambrette Fossil Lab by the player.

After completing the main story of Crown Tundra, the player is able to receive Cosmog from one of the villagers in a house in Freezington. This Cosmog gift is shiny locked.

Players can receive an Alolan Marowak, when they trade a Kantonian Marowak to the NPC inside of Fuchsia City's Pokémon Center.

This trade is infinitely repeatable. This is one of the rare instances that a received Pokémon from a NPC trade may be shiny.

Fukuoka Groudon
This Groudon can be obtained at the Fukuoka Pokémon Center by showing a staff member any of the Pokémon from the Super-Powerful event around Kyushu. The Sakura Shinkansen Pikachu cannot be used to get this Pokémon. This Wonder Card does not have the normal shiny check in place, so it is possible for it to be a shiny color-variant. Groudon and Kyogre were distributed to commemorate the one-year anniversary of the Fukuoka Pokémon Center moving to its new location.
Wondercard ID 065 PID Random Games BW Type IR Dates 03.17.2012-04.15.2012 Nickname クラードン Gender Genderless Level 80 Nature Random Ability Drought OT フクオカ SID 00000 Location PC Fukuoka Ribbon Classic Ribbon Ball Cherish Ball Held Item --- Moves Earthquake Ancient Power Eruption SolarBeam

Fukuoka Kyogre
This Kyogre can be obtained at the Fukuoka Pokémon Center by showing a staff member any of the Pokémon from the Super-Powerful event around Kyushu. The Sakura Shinkansen Pikachu cannot be used to get this Pokémon. This Wonder Card does not have the normal shiny check in place, so it is possible for it to be a shiny color-variant. Groudon and Kyogre were distributed to commemorate the one-year anniversary of the Fukuoka Pokémon Center moving to its new location.
Wondercard ID 066 PID Random Games BW Type IR Dates 04.16.2012-05.06.2012 Nickname カイオーガ Gender Genderless Level 80 Nature Random Ability Drizzle OT フクオカ SID 00000 Location PC Fukuoka Ribbon Classic Ribbon Ball Cherish Ball Held Item --- Moves Ice Beam Ancient Power Water Spout Thunder

A Jirachi that is so elusive, that there was almost no PR done for it.

There was a last minute announcement regarding this, and this Jirachi can be collected even after receiving the 0061 one.
(Blog that details it: http://co291424.com/diary/2014/diary_2014_12_14.html)
Excerpt translation of the post:
Even if you receive POKÉMON with YOU's Silicon Band [0061] and Pokésen Tohoku's [0034] different color Jirachi, you can receive it.
Thanks Kirzi for getting this rare critter for us!
 
 Species   Jirachi   Nickname   (default, save lang)   OT   ポケセン   TID   12014   Distribution   Local Wireless   Location   a Pokémon Center   Dates   Dec 14. 2014   PID   Shiny PID   Games   XYORAS    Lv. 15      Nature   Random   Ability   Serene Grace (1)   Item   Stardust 
Classic   Moves   (ITALIC means Relearnable)   Wish   Confusion   Helping Hand   Return   WC ID 70: 「いろちがいの　ジラーチ　プレゼント」's receiving text  0x35 Thank you for receiving this distribution! Please pick up your gift from the delivery girl in any Pokémon Center. いろちがいの　ジラーチ　プレゼント とうほくの　みんなに　えがおを！
いろちがいの　ジラーチを　プレゼント！

In most parts of Europe, this gift was distributed between October 1st to November 15th, 2018 via serial code,
to commemorate the Pokémon the Movie 21: The Power of Us.
In the US, the serial code is distributed at Gamestop between October 19th to November 09th, 2018.

In Australia, the receiving of the serial code from the retail chain EB Games ran from May 3rd to May 26th, and the code is valid till July 10th.
As Australia uses EU 3DS, this event uses the same copy as the one previously distributed to Europe.
     Species   Zeraora   Nickname   (default, save lang)   OT   Fula City   TID   100118   Distribution   Serial Code   Location   a lovely place   Dates   (Various)   PID   Cannot Be Shiny   Games   US & EU: USUM                                                                Lv. 50    Nature   Random   Ability   Volt Absorb (1)   Item   Air Balloon   Bundled Item   None   Card Per Save   Only One Allowed    Moves   (ITALIC means Relearnable)   Plasma Fists   Thunder Punch   Close Combat   Thunder   WC ID 668: 「Zero in on Zeraora!」's receiving text 0x2C Thank you for playing Pokémon! Please pick up your gift from the deliveryman in any Pokémon Center.

Wishing Zero in on Zeraora! The lightning-fast Mythical Pokémon
Zeraora zooms into your game
knowing Plasma Fists, which changes
Normal-type attacks into Electric-type
attacks for that turn. Format Ver.1.0.6-3, Post Updated Date:20181002_2043

In most parts of Europe, this gift was distributed between October 1st to November 15th, 2018 via serial code,
to commemorate the Pokémon the Movie 21: The Power of Us.
In the US, the serial code is distributed at Gamestop between October 19th to November 09th.

In Australia, the receiving of the serial code from the retail chain EB Games ran from May 3rd to May 26th, and the code is valid till July 10th.
As Australia uses EU 3DS, this event uses the same copy as the one previously distributed to Europe.
     Species   Zeraora   Nickname   (default, save lang)   OT   Fula   TID   100118   Distribution   Serial Code   Location   a lovely place   Dates   (Various)   PID   Cannot Be Shiny   Games   US & EU: USUM                                                                Lv. 50    Nature   Random   Ability   Volt Absorb (1)   Item   Air Balloon   Bundled Item   None   Card Per Save   Only One Allowed    Moves   (ITALIC means Relearnable)   Plasma Fists   Thunder Punch   Close Combat   Thunder   WC ID 668: 「Le Zeraora absolu !」's receiving text 0x2C Thank you for playing Pokémon! Please pick up your gift from the deliveryman in any Pokémon Center.

Wishing Le Zeraora absolu ! Zeraora, le Pokémon fabuleux plus rapide
que l’éclair, débarque et foudroie ses adversaires
avec sa capacité Plasma Punch, qui permet
en plus de changer le type des attaques Normal
en Électrik pendant un tour ! Format Ver.1.0.6-3, Post Updated Date:20181002_2045