Vivi being its own self-contained wincon via ping damage while also generating ungodly amounts of mana for a color pair that shouldnt be able to do that combine to make one of Izzets best ever Magic cards
Its a great toolbox commander that can fetch wraths (Urza's Ruinous Blast, Ugin, the Spirit Dragon), finishers (Ghalta, Stampede Tyrant, Elesh Norn, Grand Cenobite) or silver-bullet legends (Arashi, the Sky Asunder, Yasharn, Implacable Earth)
Most are instants save the one that cannot be
Dreams of Laguna This is just Think Twice, but you also get to Surveil 1 with each casting, and the flashback cost is one more mana
Legendary creatures come in all colors and mana costs and can be found in not just Commander but also formats like Modern, Legacy, Pioneer, and even Standard and booster draft Limited
Simic Whirza is the newest, most powerful iteration of it, but that could be shattered at any time