Aminatou, the Fateshifter This planeswalker allows you to control the game by flickering permanents
Teach by Example Expansion/Explosion Ral, Storm Conduit Saheeli, Sublime Artificer Thousand-Year Storm Galvanic Iteration Gandalf the Grey Melek, Izzet Paragon Saheeli Rai Protean Raider Najal, the Storm Runner Dack's Duplicate Nivix Guildmage Board Clear Despite sometimes having their experiments blow up in their faces, Izzet mages don't typically set out to make massive, board-clearing explosions
The ability to send four in the air with haste is such a powerful offensive weapon, and it really puts someone on a short clock before his ultimate is online
Black has always had its share of powerful cards throughout MTGs history, be it powerful Alpha cards like Dark Ritual and Demonic Tutor or more recent cards like Grief and Archon of Cruelty
Of course, we're not exactly impartial, but we say that the best one you can integrate into Arena is Draftsim's own Arena Tutor