There’s no consensus on the “best” blink commander. Numbers are split relatively evenly across cards like Preston, the Vanisher, Roon of the Hidden Realm and Elesh Norn, Mother of Machines, while Brago, King Eternal has his nose out just ahead of these other options. Personally, in my blink I play Omnath, Locus of Creation to give me access to red (Dockside Extortionist, Purphoros, God of the Forge and Imperial Recruiter are too good to pass up), but traditional blink decks often stick to just blue and white, for which Brago is more than adequate. Even as a card in the 99, Brago is still excellent – you’re not going to turn down a repeatable mass-blink effect.