Historic Brawl lets you bring a deck using any cards on MTG Arena—not just Standard. Pick a legendary creature or Planeswalker, fill your deck with single copies of as many powerful spells in your commander's colors as you can, and brawl against others doing the same. Will you summon armies of undead under Nicol Bolas? Will you craft wonders with Saheeli? Or will you simply smash face with the legendary Questing Beast? The choice is entirely* yours. Change your deck at any time during the event.
*Well, almost. We do have some cards that are banned. These cards are not legal in Historic Brawl events: