AllTheMons x Mega Showdown:

Adds 99% of the missing mons and some legendary (like Zarude, Lugia, Mewtwo or Rayquaza), as well as MSD item recipes (like Red/Adamant Orb) required for this addon. Also required for the Armored/Shadow Mewtwo models (for v2.0 - v2.3)

Eeveelutions Reimagined or CobbleMotion:

Both add animations to Sandy (Lana's Eevee) & their Eeveelutions. While Eeveelutions Reimagined only adds animations to the Eevee line - CobbleMotion includes animations for many other mons aswell! Use either CobbleMotion or Eeveelutions Reimagined, using both could lead to issues!

OJ's Animations:

Adds animations to Zarude (sadly this addon has since been removed from modrinth)

Gives Keldeo its resolute form appearance when held in its cosmetic slot

Gives Greninja its Ash Greninja appearance when held in its cosmetic slot

Gives Meloetta its Pirouette form appearance when held in its cosmetic slot

Gives any Zygarde its 100% form appearance when held in its cosmetic slot
This item is currently not implemented and just an idea of what's coming

How does the Shadow Type work?

General info:

• The Shadow-type has its own Tera, Z-Crystal, moves, type-effectiveness and much more
• Currently the only two Shadow Pokémon are Mewtwo & Lugia

Shadow Energy:

• To turn Pokémon into their Shadow variants you need a Shadow Energy
• Using it requires 250+ friendship with Lugia/Mewtwo and resets its friendship to 0
  

Type Chart & effectiveness:

• Shadow moves are 2x effective against every type (2x against dual types as well)
• Shadow moves are 0.5x effective against shadow itself
• Shadow Pokémon take neutral damage from all types (except Shadow) and have no immunities

Shadow Pokémon:

• Shadow Pokémon lose their original type and turn into pure Shadow-type
• Shadow Pokémon keep their original type STAB (as well as getting Shadow STAB)

Shadow Moves:

Black Vortex

• Shadow type's signature Z-Move (requires Shadowium-Z)
• Damage calculates based on the move used as a base

Max Void

• Shadow type's signature Dynamax Move
• Damage calculates based on the move used as a base
• Boosts speed of the user & allies

Shadow Blast:

• Shadow version of Aeroblast
• 80 bp, 100% accuracy, 5 pp, physical
• Has an increased critical hit ratio

Shadow Down:

• Shadow version of Screech
• 100% accuracy, 10 pp, status
• Lowers the Defense of all opponents by two stages each

Shadow Shed:

• 100% accuracy, 5 pp, status
• Removes effects of Safeguard, Reflect, & Light Screen from the opponent's field

Shadow Storm:

• 95 bp, 100% accuracy, 5 pp, physical
• Hits all opponents

How does the Crystal Type work?

General info:

• The Crystal-type has its own Tera, Z-Crystal, moves, type-effectiveness and much more
• Currently the only Crystal Pokémon are part of the Crystal Onix line

Type Chart & effectiveness:

• Crystal moves are 2x effective against Water, Ghost, Dark, Rock & Steel
• Crystal moves are 0.5x effective against Psychic & Ice
• Crystal Pokémon take 2x damage from Fire, Fighting, Rock & Steel
• Crystal Pokémon take 0.5x damage from Ice, Ground, Psychic & Fairy
• Immune to Sandstorm damage

Crystal Moves:

Glinting Beam

• Crystal type's signature Z-Move (requires Crystalium-Z)
• Damage calculates based on the move used as a base

Crystal Barrier:

• 100% accuracy, 15 pp, status
• Boosts users defense by 2 and lowers speed by 1

Crystal Cannon:

• 80 bp, 100% accuracy, 10 pp, special
• Has a 15% chance to burn the target

Crystal Veil:

• 100% accuracy, 15 pp, status
• Lowers targets accuracy by 1

Crystalline Overload:

• 130 bp, 95% accuracy, 5 pp, special
• Lowers the users special attack by 2

Max Prism

• Crystal type's signature Dynamax Move
• Boosts defense & special defense of the user & allies
• Damage calculates based on the move used as a base

Shard Strike:

• 40 bp, 100% accuracy, 30 pp, physical

Shiny Glare:

• 100% accuracy, 5 pp, status
• Traps the target on the field

Unstable Surge:

• 130 bp, 90% accuracy, 10 pp, special
• Deals a lot of crash damage to the user if it misses

Stats, Abilities and any other info:

Stats: All of them have 600 BST, with slight variations
Abilities: Intimidate/Speed Boost/Toxic Debris/Misty Surge/Stamina (same ones as in SV)
Moves: Regular Revavroom move pool, Wicked/Blazing/Noxious/Magical/Combat Torque & their boss battle moves
Notes: Can be ridden/driven by four players at once (3rd person camera can't be adjusted due to a Cobblemon bug)

How do I get them?

WILL BE ADDED IN V3.0

Use the Project Star Kit on Revavroom to switch between forms
Can be reversed by circling through all forms once

Stats, Abilities and any other info:

Stats: HP: 139, ATK: 45, DEF: 103, SP ATK: 155, SP DEF: 77, SPD: 51
Ability: Ancient Horrors (once per battle it survives using explosion/self destruct with 10% HP)
Moves: Loosely based on Gengar, with three Signature moves (check the section below for more info on those)

Signature Moves:

Gastly Assault:

A 20 bp, 95% accuracy Ghost-type special move that:

• Hits target 5x
• Deals physical damage
• Has smart targeting like Dragon Darts

Soul Leech:

A 90% accuracy Dark-type status move that:

• Traps the target
• deals 1/8% max HP damage per turn
• heals Black Fog for amount of damage dealt

Commandment:

A 100% accuracy Dark-type status move that either:

• Heals for 50% max HP
• Boost Def/SpD by one stage
• Boost SpA by two stages & raises critical hit ratio

How do I get it?

WILL BE ADDED IN V3.0

Rare spawn in Ancient Cities
Spawns more commonly at night time
Spawns in hords with up to 7 Gastly & 3+ perfect IVs

Stats, Abilities and any other info:

Shadow Lugia

Stats: Same as regular Lugia
Ability: Shadow Pressure and Shadow Guard (same abilities as regular Lugia, just different names)
Moves: Regular Lugia move pool + Shadow Blast, Shadow Shed, Shadow Down & Shadow Storm (check the Shadow-type section for more info on those)

Shadow Mewtwo

Stats: +20% Atk/SpA & -20% Def/Spd
Ability: Shadow Boost (boosts super effective moves by 1.25x)
Moves: Regular Mewtwo move pool + Shadow Blast, Shadow Shed, Shadow Down & Shadow Storm (check the Shadow-type section for more info on those)

How do I get them?

Requires ATM x MSD to obtain Lugia/Mewtwo
Requires ATM x MSD to see the Shadow Mewtwo model (only for v2.X)
Use the Shadow Energy on Lugia/Mewtwo to turn them into their Shadow Forms
Requires at least 250 friendship to use it & resets it back to 0
Can be reversed by using it again

Stats, Abilities and any other info:

Stats: HP: 106, ATK: 130, DEF: 110, SP ATK: 90, SP DEF: 154, SPD: 90
Ability: Battle Armor (prevents the opponent from landing a critical hit)
Moves: Regular Mewtwo move pool + Metal Claw, Iron Defense, Iron Head, Bullet Punch, Screech, Smart Strike, Flash Cannon, Iron Tail, Meteor Mash, Sunsteel Strike
Notes: Mega Evolves into regular Mega X/Y - tho I plan on giving it a custom mega!

How do I get it?

Requires ATM x MSD to obtain Mewtwo
Requires ATM x MSD to see the Shadow Mewtwo model (only for v2.X)
Use the Binding Armor on Mewtwo to turn it into Armored Mewtwo
Can be reversed by using it again

Stats, Abilities and any other info:

Fully Cosmetic Forms so nothing of interest here!
Costumes include the Mystery Dungeon Scarfs, as well as the Costume Party, Martial Arts, Concert, Space, Captain, Cafe, Chef, Ruins and Holiday Costumes from Unite

How do I get them?

Give Riolu/Lucario a green/red scarf to hold (cosmetic slot) to turn them into the PMD/PSMD forms
Use the Costume Box on Lucario to switch between its many outfits from Unite
Can be reversed by unequiping the scarfs or circling through all costumes

Stats, Abilities and any other info:

Fully Cosmetic Forms so nothing of interest here!
Costumes include the Astronaut, Champion, Band, Bionicle, Cafe, Dancer Shorts, Detective, El Brave, Pride Shirt (+ Ace, Bi, Pan & Trans Pride variants), Rivals of Aether, Royal Mask, Santa, Summer, Team Magma (+ OR/AS variant), Team Rocket (+ Anime variant), Team Skull & Tekken costumes

How do I get them?

Use the Costume Box on Incineroar to switch between its many outfits
Can be reversed by circling through all costumes once

Stats, Abilities and any other info:

Fully Cosmetic Form so nothing of interest here!

How do I get it?

Give Pichu an ancient light ball to hold (cosmetic slot) to turn it Spiky-Eared
Can be reversed by unequiping it

Stats, Abilities and any other info:

Stats: HP: 113, ATK: 97, DEF: 130, SP ATK: 147, SP DEF: 113, SPD: 70
Typing: Ground & Poison
Abilities: Thermal Exchange & Earth Eater
Moves: Losely based on Groudons move pool, features many fitting grass, ground & poison moves

How do I get it?

Requires ATM x MSD to obtain Groudon & the recipe for the needed red orb
Use the Corrupted wish on Groudon to turn it into Meta/Virus Groudon
Can be reversed by using it again

Stats, Abilities and any other info:

Stats: HP: 100, ATK: 140, DEF: 140, SP ATK: 180, SP DEF: 110, SPE: 110
Ability: Full Metal Body (Stats can’t be lowered by opponent)

How do I get it?

Requires ATM x MSD to obtain Dialga & the recipe for the needed adamant orb
Give Dialga a Time Gear to hold to turn it into Primal Dialga
Can be reversed by unequiping

Stats, Abilities and any other info:

Fully Cosmetic Form so nothing of interest here!

How do I get it?

Requires ATM x MSD to obtain Zarude
Give Zarude a ripped cape to hold (cosmetic slot) to turn it into Dada
Can be reversed by unequiping it

Stats, Abilities and any other info:

Shopkeeper

Basically a regular Kecleon with unique colors
The Shopkeeper is always male (it's the Kecleon Brothers afterall)

Reddy

Significantly harder to catch than regular Kecleons
Reddy is always male

How do I get them?

Both spawn in the same locations as regular Kecleons
The Shopkeeper always spawns with its brother - a regular Kecleon
Reddy is a rare spawn

Stats, Abilities and any other info:

MT:

Stats: 600 BST (100 in each stat)
Typing: Mono Steel type
Ability: Analytic

MT2:

Stats: 600 BST (100 in each stat)
Typing: Steel & Electric type
Ability: Flash Fire

How do I get them?

Ultra Rare spawns anywhere in the overworld (not near villages)
MT spawns at level 63 with its event moves and 3+ perfect IVs
MT2 spawns at level 72 with its event moves and 5+ perfect IVs

Stats, Abilities and any other info:

Snowman Munchlax

Typing: Mono Ice Type
Stats: Swapped Attack & Special Attack stats
Abilities: Ice Body, Thick Fat, Hustle (hidden)
Moves: Based on regular Munchlax + lots of ice moves
Evolution: Evolves normally into Snowman Snorlax

Snowman Snorlax

Typing: Mono Ice Type
Stats: Swapped Attack & Special Attack
Abilities: Ice Body, Thick Fat, Frosty Winds (hidden - Boosts DMG & Accuracy of Wind-Moves)
Moves: Based on regular Snorlax + lots of ice moves
Notes: Can use its Z-Move, Gmax and Gmax-Replenish normally

How do I get them?

Rare spawn in snowy biomes

Stats, Abilities and any other info:

Illusionary Rayquaza

Typing: Ghost/Flying type
Stats: Same as Rayquaza, SpD & Spe raised to 105 to match Mismagius'
Moves: A combination of both Mismagius' & Rayquazas move pools

Illusionary Mega Rayquaza

Typing: Dragon/Flying type (due to coding limitations on my end)
Stats: Same as Mega Rayquaza

How do I get it?

Requires ATM x MSD to obtain Rayquaza
Use Dream Catcher on a Mismagius and afterwards on a Rayquaza
Can be reversed by using the item again

Stats, Abilities and any other info:

All Eeveelutions of Sandy have their own unique Hairstyles
Evolution: Evolves normally into all eevee evolutions
Notes: Can use its Z-Move, Gmax and Gmax-Cuddle normally

How do I get them?

Rare spawn in Woodland Mansions
Give Eevee or any Eeveelution shears to hold (cosmetic slot) to turn it into Sandy
Can be reversed by unequiping it

Stats, Abilities and any other info:

Mimikins is always female and its shiny is inverted
Notes: Can use its Z-Crystal & Ability normally

How do I get it?

Ultra-Rare spawn in the Deep Dark

Stats, Abilities and any other info:

Stats: HP: 105, ATK: 164, DEF: 130, SP ATK: 50, SP DEF: 130, SPD: 101
Moves: Expanded its move pool to closer reflect his appearance in the manga
Notes: Cannot Mega evolve, breed, or be evolved into

Custom Z Move/Crystal:

Dark Tyranitarium-Z transforms the move Rock Wrecker into Kaiju Cataclysm
Hits all Pokémon on the field, removes terrain, raises both its defenses & makes all targets flinch

How do I get it?

Ultra rare spawn at level 100 in naturally generated villages (Vanilla & BCA)

Stats, Abilities and any other info:

Crystal Onix

Typing: Crystal Type
Moves: Has a custom move pool with a few crystal moves added (read more about them in the "Custom Types" section)
Stats: HP: 60, ATK: 45, DEF: 130, SP ATK: 70, SP DEF: 80, SPE: 50
Abilities: Brittle Crystal (when hit gain +2 speed, -1 defense, attacker takes 1/8 of their HP as damage) & Crystalline (changes all rock moves to Crystal type & boosts their damage by 20%)
Evolution: Feed it 600 Crystals (amethyst shards count as 1, small buds 2, medium 4, large 6 & clusters as 8) then you can evolve it at level 40+ at dawn (sunrise)

Crystal Steelix

Typing: Crystal Type
Moves: Has a custom move pool with a few crystal moves added (read more about them in the "Custom Types" section)
Stats: HP: 90, ATK: 45, DEF: 180, SP ATK: 120, SP DEF: 90, SPE: 35
Abilities: Brittle Crystal (when hit gain +2 speed, -1 defense, attacker takes 1/8 of their HP as damage) & Crystalline (changes all rock moves to Crystal type & boosts their damage by 20%)
Mega Evolution: Requires Crystalline Steelixite

Crystal Mega Steelix

Typing: Crystal Type
Stats: HP: 90, ATK: 40, DEF: 212, SP ATK: 166, SP DEF: 122, SPE: 30
Ability: Hall of Mirrors (15% chance that the attacker will miss and become confused instead)

How do I get it?

Crystal Onix is a rare spawn in caves/underground, Crystal Steelix has to be evolved into & Mega Crystal Steelix requires you to use the Crystalline Steelixite Mega Stone

Stats, Abilities and any other info:

Levelling: They require less EXP to level up (fast experience group)
Notes: They can mega evolve normally

How do I get them?

Put a Nether Star and a Charcoal Stick/Miracle Seed/Mystic Water into a Resurrection Machine
They come with 4+ random perfect IVs