Its MTG Lifelink ability also makes it a great source of life gain
The play pattern here is to get Vivi in play, pitch a huge red spell card to cast a free Blazing Shoal and make Vivi enormous, then use Vivi's ability to generate loads of free mana and cast more giant spells, storm off, or simply swing and deal heaps of damage to your opponent with the now embiggened mage
You let your opponent draw as many cards as you take out, and that means you really need to know what you are looking for
When taken all together, what you have is a colorless Glorious Anthem with an unconditional discount on all your spells, on top of completely shutting down all planeswalkers
Sail the Azurite Sea Sail the Azurite ekes out the number three spot on this list above Tipo - Growing Son, but just barely
I think Ral is definitely above the line for Modern playable, and some Jeskai decks use one in place of a Teferi