The official Pokémon website has announced the details for the Ranked Battles Series 8 for Pokémon Sword and Pokémon Shield which begins on February 1st, 2021.

Trainers Can Use a Restricted Pokémon in Ranked Battles Series 8, Starting February 1, 2021

Prepare for huge battles in Pokémon Sword and Pokémon Shield with the latest Ranked Battle Series.

Ranked Battle Series 8 starts up on February 1, 2021, in Pokémon Sword and Pokémon Shield, and with it comes a chance to battle together with tough Legendary Pokémon usually not permitted in competitive matches. Trainers can include one Pokémon from the Restricted Pokémon list below on their Battle Team. Note that this is different from previous GS Cup regulations where two of these Pokémon were permitted on a Battle Team. The new team restrictions closely match the recent Dragon King Cup competition, so check out battle data from that tournament in Pokémon HOME to get some team ideas!

The Series 8 regulations will also be in effect for the Pokémon Players Cup III Region Qualifier and Global Finals rounds.

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

• Restricted 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, 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.
• Pokémon with the Gigantamax Factor are permitted.
• 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 Battle Series 8 starting February 1!

Source: https://www.pokemon.com/us/pokemon-news/trainers-can-use-a-restricted-pokemon-in-ranked-battles-series-8-starting-february-1-2021/