List of Pokémon forms by release date/2021

January
Genesect Burn Drive and shiny Snivy were released at the start of Unova Celebration Event.

Regular (1) =

Shiny (3) = PS Snivy (495) PS Servine (496) PS Serperior (497)

January
Male Frillish was released at the start of second half of GO Battle League Season 6. Female form had not been released yet.

Regular (2) =

January
Shiny Buizel was released at the start of Sinnoh Celebration Event.

Shiny (2) = PS Buizel PS Floatzel

January
Mega Ampharos was released.

Regular (1) =

Shiny (1) = PS Ampharos

January
Shiny Miltank was released at the start of Johto Celebration Event.

Shiny (1) = PS Miltank

February
Mega Gyarados was released at the start of Lunar New Year 2021.

Regular (1) =

Shiny (1) = PS Gyarados

February
Munna and shiny Spinda pattern 9 and Alomomola were released at the start of Valentine's Day 2021.

Regular (2) =

Shiny (2) = PS Spinda PS Alomomola

February
Shiny Spearow, Paras, Hitmonlee, Hitmonchan, Ditto, Snorlax and Mew were released at the start of Pokémon GO Tour: Kanto. Since then, all Shiny forms of Kanto-region Pokémon were released.

Shiny (9) = PS Spearow PS Fearow PS Paras PS Parasect PS Hitmonlee PS Hitmonchan PS Ditto PS Snorlax PS Mew

March
Shiny Landorus and Spring form Deerling were released. Female Frillish was also released at the start of this day, being only the male version available before.

Regular (2) =

Shiny (1) = PS Landorus

March
Shiny Tornadus was released, and shiny Fletchling was released at the start of March 2021 Community Day.

Shiny (4) = PS Tornadus PS Fletchling PS Fletchinder PS Talonflame

March
Shiny Nosepass was released at the start of Searching for Legends.

Shiny (2) = PS Nosepass PS Probopass

March
Shiny Thundurus was released.

Shiny (1) = PS Thundurus

March
Mega Manectric, Therian Thundurus and Tynamo were released at the start of Charge Up.

Regular (5) =

Shiny (1) = PS Manectric

March
Shiny Rainy Castform was released at the start of Weather Week.

Shiny (1) = PS Castform

March
Therian Tornadus was released.

Regular (1) =

April
Mega Lopunny and shiny Bunnelby was released at the start of Spring into Spring 2021.

Regular (1) =

Shiny (3) = PS Lopunny PS Bunnelby PS Diggersby

April
Therian Landorus, Skrelp and Clauncher were released at the start of Rivals' Week. Kalos Silver medal became achievable for the first time.

Regular (5) =

April
Binacle and shiny Trubbish were released at the start of Sustainability Week 2021.

Regular (2) =

Shiny (2) = PS Trubbish PS Garbodor

April
Shiny Smeargle was released at the start of New Pokémon Snap Celebration.

Shiny (1) = PS Smeargle

May
Spritzee, Swirlix, Goomy and Xerneas were released at the start of Luminous Legends X Part 1.

Regular (9) =

May
Pancham and shiny Galarian Ponyta were released at the start of Luminous Legends X Part 2.

Regular (2) =

Shiny (2) = PS Ponyta PS Rapidash

May
Mega Altaria was released after May 2021 Community Day.

Regular (1) =

Shiny (1) = PS Altaria

May
Yveltal was released at the start of Luminous Legends Y Part 1.

Regular (1) =

May
Sylveon and shiny Galarian Zigzagoon were released at the start of Luminous Legends Y Part 2.

Regular (1) =

Shiny (4) = PS Zigzagoon PS Linoone PS Sylveon PS Obstagoon

May
Mienfoo was released at the start of GO Battle League Season 8.

Regular (2) =

June
Galarian Slowking was added to game files, rising up Johto-region Pokédex to 129 distinct forms.

June
Galarian Slowpoke and Mega Slowbro were released at the start of A Very Slow Discovery.

Regular (3) =

Shiny (1) = PS Slowbro

June
Shiny Regigigas was released at the start of Summer Solstice 2021.

Shiny (1) = PS Regigigas

June
Shiny Bidoof was released at the start of Bidoof Breakout.

Shiny (2) = PS Bidoof PS Bibarel

July
Shiny Tepig was released at the start of July 2021 Community Day.

Shiny (3) = PS Tepig PS Pignite PS Emboar

July
Shiny Darumaka was released at the start of the 5th Anniversary.

Shiny (2) = PS Darumaka PS Darmanitan

July
Meloetta and Shiny F Unown, Whismur, Chimecho, Audino, Tympole, Throh and Sawk were released at the start of Pokémon GO Fest 2021.

Regular (1) =

Shiny (11) = PS Unown PS Whismur PS Loudred PS Exploud PS Chimecho PS Audino PS Tympole PS Palpitoad PS Seismitoad PS Throh PS Sawk

July
Shiny Cranidos, Shieldon and Dialga were released at the start of Ultra Unlock Part 1: Time.

Shiny (5) = PS Cranidos PS Rampardos PS Shieldon PS Bastiodon PS Dialga

August
Shiny Heracross and Palkia were released at the start of Ultra Unlock Part 2: Space.

Shiny (2) = PS Heracross PS Palkia

August
Skwovet, Wooloo, Falinks, Zacian, and Shiny Galarian Meowth, Farfetch'd, Weezing and Stunfisk were released at the start of Ultra Unlock Part 3: Sword and Shield. Galar Bronze medal became achievable for the first time in preparation for the event. Also, all Galar-region Pokémon were made available, rising up Galar-region Pokédex to 89 Pokémon species and 95 distinct forms.

Regular (6) =

Shiny (6) = PS Meowth PS Farfetch'd PS Weezing PS Stunfisk PS Perrserker PS Sirfetch'd

August
Zamazenta was released at the start of later part of Ultra Unlock Part 3: Sword and Shield.

Regular (1) =

September
Hoopa was released at the start of Hoopa's Arrival.

Regular (1) =

September
Inkay was released at the start of Psychic Spectacular 2021.

Regular (2) =

September
Shiny Uxie, Mesprit and Azelf were released.

Shiny (3) = PS Uxie PS Mesprit PS Azelf

September
Shiny Oshawott was released at the start of September 2021 Community Day.

Shiny (3) = PS Oshawott PS Dewott PS Samurott

September
Furfrou in 9 trims and Shiny Blitzle were released at the start of Fashion Week 2021.

Regular (9) =

Shiny (1) = PS Blitzle

September
Shiny Zebstrika was released after Fashion Week 2021, as only collar Blitzle, which could not evolve, was available during Fashion Week.

Shiny (1) = PS Zebstrika

October
Zarude was released at the start of Secrets of the Jungle Event 2021. Douse Drive Genesect was released.

Regular (2) =

October
Galarian Slowking and Shiny Spinarak were released at the start of Halloween 2021 Part 1.

Regular (1) =

Shiny (2) = PS Spinarak PS Ariados

October
Mega Absol, Phantump and Pumpkaboo were released at the start of Halloween 2021 Part 2.

Regular (11) =

Shiny (1) = PS Absol

November
Dedenne was released at the start of Festival of Lights 2021.

Regular (1) =

November
Shiny Vullaby was released at the start of A Looming Shadow Returns!.

Shiny (2) = PS Vullaby PS Mandibuzz

November
Hoopa Unbound was released at the start of Mischief Unbound.

Regular (1) =

December
Mega Steelix, and Shiny Reshiram and Zekrom were released at the start of Season of Heritage.

Regular (1) =

Shiny (3) = PS Steelix PS Reshiram PS Zekrom

December
Druddigon, along with its shiny form, was released at the start of Dragonspiral Descent.

Regular (1) =

Shiny (1) = PS Druddigon

December
Shiny Spheal and Kyurem were released at the start of Holiday 2021 Part 1.

Shiny (4) = PS Spheal PS Sealeo PS Walrein PS Kyurem

December
Bergmite and Shiny Galarian Darumaka were released at the start of Holiday 2021 Part 2. Kalos Gold medal became achievable for the first time.

Regular (2) =

Shiny (2) = PS Darumaka PS Darmanitan

December
Shiny Hoothoot was released at the start of New Year's 2022.

Shiny (1) = PS Hoothoot