Here is a list of all Community Day events and featured Pokemon in Pokemon Go so far (2018, 2019, 2020, and 2021)
Community Day List 2018
- January 20 – Pikachu
- February 24 – Dratini
- March 25 – Bulbasaur
- April 15 – Mareep
- May 19 – Charmander
- June 16 – Larvitar
- July 8 – Squirtle. As a surprise, Niantic released Squirtle with sunglasses
- August 11 and ended the next day, on August 12 featuring Eevee
- September 22 – Chikorita
- October 21 – Beldum
- November 10 – Cyndaquil
- November 30-December 2 – all previous Special Pokemon
Community Day List 2019
- January 12 – Totodile
- February 16 – Swinub
- March 23 – Treecko
- April 13 – Bagon
- May 19 – Torchic
- June 8 – Slakoth
- July 21 – Mudkip
- August 3 – Ralts
- September 15 – Turtwig
- October 12 – Trapinch
- November 16 – Chimchar
- December 14 and 15
Community Day List 2020
- January 19 – Piplup
- February 22 – Rhyhorn
- March 15 Abra POSTPONED
- April 25 – Niantic and Pokemon Go introduced the first Community Day: Stay at Home Edition, featuring Abra
- May 24 – Seedot
- June 20 – Weedle
- July 19 – Gastly
- August 8 – Magikarp
- September 20 – Porygon
- October 17 – Charmander
- November 15 – Electabuzz
- November 21 – Magmar
- December 2020 Community Day – December 12 and December 13
Community Day List 2021
- January 16 – Machop
- February 7 – Roselia
- March 6 – Fletchling
- April 11 – Snivy
- May 15 – Swablu
- June 6 – Gible
- July 3 – Tepig
- August 14 and 15 – Eevee
- September, 19 – Oshawott
- October 10, 17 or 24
- November 13 or 20
- December 19 or 26
https://www.futuregamereleases.com/2021/08/pokemon-go-list-of-all-community-day-events-and-featured-pokemon-so-far-2018-2019-2020-and-2021/