Format refers to the ways you can play standard matches. Playing in Rotation format allows you to play using the five most recent card sets and basic cards in a match. Unlimited format allows you to use all available cards in a match.
In Rotation format, you can use the five most recent card sets and basic cards in a match. This format is recommended for players new to Shadowverse.
Usable Cards as of Dec 28, 2017
3rd Card Set: Rise of Bahamut
4th Card Set: Tempest of the Gods
5th Card Set: Wonderland Dreams
6th Card Set: Starforged Legends
7th Card Set: Chronogenesis
Basic cards (starter cards, main story rewards, Harnessed Flame, Harnessed Glass)
In Unlimited format, players can use all available cards. Note that there may be some restrictions placed on cards.
One-Card Restrictions as of Jan 29, 2018
Aria, Guiding Fairy