theSLAYER

Ahiru's Wonderland is apparently an infamous site that hoards event Pokemon from Japan, back in Gen 3 days.

Relevant screenshots of the page will match the relevant save data uploaded.
 
Jan 1, 2019 edit: @shadowofdarkness shared some files he downloaded, probably back in 2007.
Interestingly, it went beyond Gen 3, and contained various Gen 4 files.

Do note that:
1. .stk files are a bulk batch of files used with pokestock
2. There appears to be some files being marked (with Pokerus) in the saves, use at your own risk.

In Pokémon Colosseum, players are given the MATTLE Ho-Oh after they complete the 100 Battle Challenge!
Other conditions include snagging and purifying all 48 Shadow Pokémon, and using a team only from the story mode, in the Battle Mode.
More Colosseum and XD Pokémon can be found at this page.

This event was distributed via Nintendo Zones at Pokemon Centers and Pokemon Store outlet in Japan.
This marks the first time Diancie is obtainable shiny.
 Species   Diancie   Nickname   (default, save lang)   OT   ポケセン   TID   12125   Distribution   Nintendo Zone   Location   a Pokémon Center   Dates   Dec 12 to Dec 31, 2015   PID   Shiny PID   Games   JP 3DS: ORAS    Lv. 50      Nature   Random   Ability   Clear Body (1)   Item   Normal Gem 
Classic   Moves   (ITALIC means Relearnable)   Diamond Storm   Moonblast   Reflect   Return   WC ID 131: 「いろちがいのディアンシー　プレゼント」's receiving text  0x07 Thank you for coming to the Pokémon Center! Please pick up your gift from the delivery girl in the game. いろちがいのディアンシー　プレゼント ポケモンセンターから　かんしゃを　こめて
とっておきの　プレゼント！
いままで　だれも　みたことのない
いろちがいのディアンシーを　プレゼント！

Here are two saves to the game My Pokémon Ranch (non Japanese versions).

The file My Pokemon Ranch.rar is from @thaleskpl (submitted to digiex), where the Mew and Phione are ready to be redeemed.
All the player has do to is to send an egg and Leafeon over to complete the trade.
The file my poke ranch new save.rar is from @yeison_diaz (submitted to here), where the Mew and Phione and a few others has already been redeemed, but it appears there's some trades from Hayley that may still be available.

Thanks to the research into the save structure done by @suloku, the tradable Pokémon have already been extracted and added to the existing entries in our In-Game Series > Pokémon Ranch area.

Pokémon Legends Arceus introduced the concept of Noble Pokémon to the Pokémon lore. These nobles are descendants of Pokémon that journeyed alongside the ancient hero across Hisui. During the story, lightning bolts from the space-time distortion will hit some of the Noble Pokémon, causing them to go on a frenzy, and taking on their Lord/Lady form (the yellow texture). It is to note that Lord Avalugg is significantly larger than all Pokémon, comparable to a mountain than a Pokémon.
 
In the game, the lord/lady forms were actually designated as an extra form in the data. However, if one were to hack one in via save editing into the PC/Party, the form 'reverts' to the appearance it normally has, akin to the game force reverting Mega Evolutions and Eternamax Eternatus in previous games.


However, there are some ways to get around it:
1) RAM inject the mon
2) Save edit the mon into the farm (as of ver1.0.2, this still works, but I expect it to get patched at some point) [example here]
3) Receive one that is properly in lord/lady form from trade


This Avalugg was caught using cheats; 1. I repeated the noble fight, 2. used a cheat to teleport away, 3. engaged a fight with another species (allowing me to access balls in the UI again), 4. going back to the lord and throwing balls at it.

In Pokémon Legends Arceus, the player is able to give or loan mons to the NPCs, and those mons will show up in the overworld.

Even for permanent gifts, the data of the given mons are actually fully intact.

This plugin allows you to modify the mons that were given/on loan.

 
How to use
Put the plugin into the plugins folder in your PKHeX directory, then access it from the Tools menu.
Note: Win 10 might block DLL files downloaded from the internet. In that case right click the plugin file, go to properties and check "unblock" (as seen here).
[You may have to unblock, reblock, then unblock again to get it to work]
 Example of how to unblock:


Usages
Used to modify the mons in NPC/farm block in the save.
Always back up your saves before you perform any edits.
 
Support
Pokémon Legends Arceus


For help and bug reporting, go here.

Credits
Kaphotics for PKHeX.

In the game Pokémon Sapphire, Latias roams Hoenn after the player's first entry into the Hall of Fame and watches the TV broadcast in the player's living room.

In the game Pokémon Emerald, the same conditions as above apply, with an additional condition:
the player must choose Red after watching the TV broadcast.
Because of the Roamers IV Glitch, roamers in Gen III will have weak IVs (besides Hit Points).
As a result, the Hidden Power of roamer will always be Fighting Type.
Pokémon Emerald isn't affected by the glitch, however.

Besides events that distribute Phione (or a trade with My Pokémon Ranch),
Phione can only be obtained by breeding Ditto with Manaphy/Phione.

Species   Diancie   Nickname   (default, save lang)   OT   올스타   TID   08136   Distribution   Infrared   Location   a Pokémon event   Dates   Aug 13 to Aug 14, 2016   PID   Shiny PID   Games   All Regions 3DS: XYORAS                                                               Lv. 50    Nature   Random   Ability   Clear Body (1)   Item   Normal Gem   Card Per Save   Only One Allowed    Moves   (ITALIC means Relearnable)   Diamond Storm   Moonblast   Reflect   Return   WC ID 1071: 「색이 다른 디안시 선물」's receiving text 0x2E Thank you for participating in a Pokémon Video Game event! Please pick up your gift from the delivery girl in any Pokémon Center.

Event 색이 다른 디안시 선물 포켓몬 이벤트에 오신 여러분에게
색이 다른 디안시를 선물합니다.
메가진화로도 진화시켜보세요! Format Ver.1.0.6-2, Post Updated Date:20180412_0716

A Greninja with Battle Bond, that can transform to Ash-Greninja form!
This wonder card is sent from the Demo to your main Pokemon Sun or Pokemon Moon game.
(Language of Wondercard is determined by language of Demo, Not language of Main game save)
 
 Species   Ash-Greninja (Inactive)   Nickname   (default, in )   OT   Ash   TID   131017   Distribution   Pokemon Demo   Location   the Kalos region   Dates   Any Date   PID   Specified: 8994A7D9   Games   SM    Lv. 36     Met Lv. 5                                                                  Nature   Random   Ability   Battle Bond (1)   Item   None   Bundled Item   None 
Souvenir   Moves   (ITALIC means Relearnable)   Water Shuriken   Aerial Ace   Double Team   Night Slash   WC ID 2046: 「Special Demo Version Ash-Greninja」's receiving text 0x5B Thank you for playing the demo version! Please pick up your gift from the deliveryman in any Pokémon Center.

Species   Tyranitar   Nickname   (default, save lang)   OT   ヤミらみこ   TID   03866   Distribution   Nintendo Zone   Location   Route 7   Dates   Nov 07 - Dec 06, 2015   PID   Shiny PID   Games   Given to: JP 3DS: ORAS 
Preset as: X                                                                Lv. 55     Met Lv. 1    Nature   Adamant   Ability   Sand Stream (1)   Item   Life Orb   Card Per Save   Only One Allowed    Moves   (ITALIC means Relearnable)   Crunch   Rock Slide   Low Kick   Protect   WC ID 130: 「チャンピオンの　バンギラス」's receiving text 0x07 Thank you for coming to the Pokémon Center! Please pick up your gift from the delivery girl in the game.

Battle Champ チャンピオンの　バンギラス ポケモンWCS'15 ジュニアチャンピオンの
ポケモンを　プレゼント！
けっしょうせんで　かつやくした
いわなだれを　つかって
そのつよさを　たいけんしよう！ Format Ver.2.1.2-2, Post Updated Date:20210823_1608

This is a Wild Area event held by Sword and Shield.  This event does not appear to host any Gigantamaxes.
This appears to be the default max event raids that Sword and Shield will use going forward (ignoring the monthly 1 week events).
This "monthly default"  went into use starting April 2021.
 
To import these files into your save, use PKHeX's block importing function. Our tutorial should guide you through it.
Our first post of this page contains some data relevant to the importing stage.
There's info and some common questions regarding Wild Area Events here.
To see other Wild Area Events, here.

In the games Pokémon X & Y, when the player first meets Professor Sycamore in his laboratory in Lumiose City,
the player is given a choice to take Bulbasaur, Charmander or Squirtle, as well as the corresponding Mega Stone.

Add custom skins to your official VC dumps! Swap games around!
 
Original Link:
https://gbatemp.net/threads/discussion-new-super-ultimate-injector-nsui.500376/

Using the Aurora Ticket received from events on their copy of Pokémon FireRed & LeafGreen, or Pokémon Emerald games,
players gain access to the Birth Island, and get a chance to capture to Mythical Deoxys!
For players who rather not use the Mystery Gift to activate the event, simply use PKHeX's Event Flags > Research, and
For Pokémon FireRed & LeafGreen: Check Flag 2122 and 2123
For Pokémon Emerald: Check Flag 0314 and 2261
then proceed to add an Aurora Ticket into the Key Items of the Bag.

For Pokémon FireRed & LeafGreen, having the National Dex and Rainbow Pass may be required. More event flags here.

The shiny Deoxys here is obtained via Tool Assisted RNG.

This page has the wonder card for the Mystic Ticket.
Note that the versions for FireRed and LeafGreen Versions and Emerald Version are not interchangeable.


Original Thread and Credits!

PKHeX plugin to check for valid PIDIV and other correlated stats for Overworld8 or Max Raid or Max Lair mons.
Once the data is found, the selected row can be sent to PKHeX's viewer, without the user having to copy the data over manually.

Other small features include:
- Able to update Trainer ID/Secret ID in Searcher based on Save's details or Viewed Pokémon's details
- Able to update Trainer ID/Secret ID in Searcher based on viewed Pokémon's details, whenever a different Pokémon is viewed
- Able to update Gender Ratio filter (Max Raids/Max Lair searching only) based on the viewed Pokémon
- The TSV box updates based on what the user inputs, or the data grabbed from save/viewer.
- If a modified IV stat is 31, the Hyper Training Flag would be removed
 
Spiritual successor of IV Searcher portion found here: https://projectpokemon.org/home/files/file/4447-gen-8-ow-shiny-pid-genner/
 

How to use
Put the plugin into the plugins folder in your PKHeX directory, then access it from the Tools menu.
Tutorial, under Searching for Particular IVs: https://projectpokemon.org/home/tutorials/save-editing/using-pkhex/pid-mismatch-origin-game-swsh-r114/
Note: Win 10 might block DLL files downloaded from the internet. In that case right click the plugin file, go to properties and check "unblock" (as seen here).
[You may have to unblock, reblock, then unblock again to get it to work]
Example of how to unblock:
 
Support
Sword and Shield.
BDSP

For help and bug reporting, go here.


Credits
Kaphotics for PKHeX, his documentation on Github, as well as other various functions found in PKHeX.Core and PKHeX.Drawing
SkyLink98 with helping me figure out how to deal with implementing changes on PKHeX's viewer
Leanny's Source code for Ability and Gender determination for raid stats from seed.
Admiral Fish's Raid stats generation write-up.
SciresM and his Roaming8b code write-up used by PKHeX.

When players logged into Pokémon GO during the period of October 1st to October 10th (2021), they gain access to the special research that yields a Zarude upon completion. Players do not need to complete the research within the period.
The special research was available to players to promote the then upcoming movie Pokémon M23: Secrets of the Jungle, which would have been aired on Netflix.

For this file to be transferable across games without any stats oddities, you cannot modify any immutable values.
Read here: Relevance of HOME tracker

This is a Wild Area event held by Sword and Shield. This event gives players a chance to capture the Alolan Starters.
An interesting note, is you could try to catch them with other types of Poké Balls, which couldn't be done previously.
Only the files normal_encount, normal_encount_rigel1, normal_encount_rigel2, and dai_encount were updated to Index 87.
 
To import these files into your save, use PKHeX's block importing function. Our tutorial should guide you through it.
Our first post of this page contains some data relevant to the importing stage.
There's info and some common questions regarding Wild Area Events here.
To see other Wild Area Events, here.

PKHeX plugin to check the details of any Overworld/Fishing mons roaming around when the player saved.
This is a viewer, not an editor.
Spiritual successor of
How to use
Put the plugin into the plugins folder in your PKHeX directory, then access it from the Tools menu.
Note: Win 10 might block DLL files downloaded from the internet. In that case right click the plugin file, go to properties and check "unblock" (as seen here).
[You may have to unblock, reblock, then unblock again to get it to work]
 Example of how to unblock:
 
Support
Sword and Shield


For help and bug reporting, go here.

Credits
Kaphotics for PKHeX, his documentation on Github, as well as other various functions found in PKHeX.Core, PKHeX.Drawing, PKHeX.Drawing.Misc, and PKHeX.Drawing.PokeSprite

This gift was distributed at the Gotta catch 'em all! STATION in Pokémon Center New York.

PKHeX plugin to import Wonder Cards as Wonder Record (entries that show up in the Gift Album).
For SWSH, the 50 slots can be viewed via Sprite Representations: Pokémon represented by the relevant sprites; Items represented by relevant sprites (note: only the first item slot of that gift, not all); the Black Ball can represent Clothes, Money, and BP gift type; Blank represents the slot being unused.
(Note: As WR don't store shininess, shininess is only determined by one particular gift title. WR also doesn't store Gmax flag, so it depends on the one particular gift title.)

This edit is merely affects what show up in the Gift Album (cannot be redeemed in-game), but some people want it, so here it is.

Reminder: Due to changes made starting from LGPE, injecting Wonder Cards (or Wonder Records, for that matter) won't allow the gift to be redeemed in-game.
 
How to use
Put the plugin into the plugins folder in your PKHeX directory, then access it from the Tools menu.
Note: Win 10 might block DLL files downloaded from the internet. In that case right click the plugin file, go to properties and check "unblock" (as seen here).
[You may have to unblock, reblock, then unblock again to get it to work]
 Example of how to unblock:


Usages
Used to view the Wonder Records in the KMysteryGift block in the save.

Can be used to inject and extract WR8. Can be used to convert WC8 to WR8.
Both injections can be used via the button or dragging the file into the form.
Do note the conversion is based on best approximation from the data observed. Use at your own risk!

Can be used to manipulate the timestamp on entries.
Always back up your saves before you perform any edits.
 
Support
PLA & BDSP (to a limited extent)
Sword and Shield - Viewing, WR8 Injection, WC8 -> WR8 Injection, Timecode manipulation
Let's Go Pikachu & Eevee - Viewing (WR7 Injection and Extraction can be done natively using PKHeX)


For help and bug reporting, go here.

Credits
Kaphotics for PKHeX.

This is a Wild Area event held by Sword and Shield. This event gives players a chance 2% to find a guaranteed Shiny Solrock or Shiny Lunatone in 5-star raids.
Only the files normal_encount, normal_encount_rigel1, normal_encount_rigel2, and dai_encount were updated to Index 85.
 
To import these files into your save, use PKHeX's block importing function. Our tutorial should guide you through it.
Our first post of this page contains some data relevant to the importing stage.
There's info and some common questions regarding Wild Area Events here.
To see other Wild Area Events, here.

PKHeX plugin to edit GO Park Storage.

User can click on the slot to view the content of the slot.
User may edit the GP1 in the viewed slot.
User can also import a GP1 into the viewed slot via the button or dragging it in.
User may also delete the GP1 in the viewed slot.
Given the GO CP on file isn't carried into the game visually, and appears to be unused data, GO CP calculation isn't included.
(If you need it, it is here on an external program)


For help and bug reporting, go here.
 
How to use
Put the plugin into the plugins folder in your PKHeX directory, then access it from the Tools menu.
Let's Go Pikachu and Let's Go Eevee is supported.
Note: Win 10 might block DLL files downloaded from the internet. In that case right click the plugin file, go to properties and check "unblock" (as seen here).
[You may have to unblock, reblock, then unblock again to get it to work]
 Example of how to unblock:

Credits
Kaphotics for the making of PKHeX, as well as documented structure for various GP1 parts.
BlackShark for his meticulous work with the Feebas Locator [Full disclosure: I've never made a PKHeX plugin before, so had to look at his work to figure it out]
 

Movie 2012 Keldeo
This Keldeo was given to players who had purchased advance tickets to the 15th Pokémon movie. This was the first time Keldeo was released. If brought to the Moor of Icirrus along with Cobalion, Terrakion, and Virizion, this Keldeo can learn the move Secret Sword. Bringing it to the Pledge Grove in Black 2 or White 2 will teach it the same move and change it into its Resolute Form.
Wondercard ID 069 PID Random Games BW B2W2 Type IR Dates 06.23.2012-08.31.2012 Nickname ケルディオ Gender Genderless Level 15 Nature Random Ability Justified OT しょこたん SID 00000 Location Pokémon Movie 12 Ribbon Wishing Ribbon Ball Cherish Ball Held Item PP Max Moves Aqua Jet Leer Double Kick BubbleBeam