While I don't expect the bird deck to win a Pro Tour or anything, I had a blast playing it and expect to see plenty of it on MTG Arena and local events
Ultima The five-mana board sweeper, Ultima, is seeing play primarily in Domain Overlords and Azorius Control
Perhaps the Royal Vizier, because well be combo-ing with steel for this one
Ultima is relevant for a few key reasons, the main one being it destroys your opponent's copies of Cori-Steel Cutter
Though, depending on how Voldaren Thrillseeker will be replaced post-rotation, the Agatha's Soul Cauldron variant may be just as viable in regularly climbing the rank ladder as well
Where its likely to suffer the most is in protracted battles with Ruby Decks that can clear your hard work with Be Prepared, or against Steel decks that can obliterate your characters more easily than you can theirs.