The Pokémon official website has announced the details for the Pokémon Sword and Pokémon Shield Ranked Battles Series 12 and it uses the GS Cup format, which allows Trainers to include two Pokémon from the Restricted Pokémon list below on their Battle Team.

Bring Two Restricted Pokémon into Ranked Battles Series 12, Now Under Way

The latest Pokémon Sword and Pokémon Shield Ranked Battles Series also allows Trainers to have a Pokémon Dynamax during battle.

Ranked Battles Series 12 is under way in Pokémon Sword and Pokémon Shield, and with it comes another chance to battle together with tough Legendary Pokémon usually not permitted in competitive matches. Unlike recent Ranked Battles Series, Series 12 will use the GS Cup format, which allows Trainers to include two Pokémon from the Restricted Pokémon list below on their Battle Team. Trainers will also be allowed to have one of their Pokémon Dynamax or Gigantamax during battle!

The Series 12 regulations will be used for Video Game Championship Series events in 2022, as well as in some online competitions. For a summary of all Video Game Championships tournament rules, see below. You can also check out the Play! Pokémon Rules & Resources page to see complete Play! Pokémon VG rules and formats.

Eligible Pokémon

Mewtwo, Lugia, Ho-Oh, Kyogre, Groudon, Rayquaza, Dialga, Palkia, Giratina, Reshiram, Zekrom, Kyurem, Xerneas, Yveltal, Zygarde, Cosmog, Cosmoem, Solgaleo, Lunala, Necrozma, Zacian, Zamazenta, Eternatus, and Calyrex

• Mythical Pokémon are not permitted in battle.
• All other Pokémon from the Galar Pokédex, the Isle of Armor Pokédex, and the Crown Tundra Pokédex as well as certain other Pokémon are permitted.
• Only Pokémon obtained in Pokémon Sword or Pokémon Shield or those with the battle-ready symbol are eligible.
• Pokémon will be allowed to Dynamax.
• All Pokémon will be set to Lv. 50, including Pokémon below Lv. 50.
• Duplicate Pokémon are not allowed.
• Duplicate held items are not allowed.

Timer Regulations

• Each battle begins with a 90-second Team Preview phase.
• In each battle, players have the following time limits.
  • 7 minutes of Your Time
  • 45 seconds of Move Time
  • 20 minutes of Game Time

Good luck battling in Pokémon Ranked Battles Series 12!

Source: https://www.pokemon.com/us/pokemon-news/bring-two-restricted-pokemon-into-ranked-battles-series-12-now-under-way/