Our mana rocks like Astral Cornucopia, Everflowing Chalice, Empowered Autogenerator, Mindsplice Apparatus all generate more mana as we proliferate, our storage lands like Dreadship Reef also become huge rituals, Vat of Rebirth and Lux Cannon get way more effective, we can speedrun through sagas like Phyrexian Scriptures and so much more
If you play Turn 3 Righteous Valkyrie at twenty life, on Turn 4 you could cast Inquisitor Captain, hit a four-toughness Angel, and already get yourself to 27 life to turn the Valkyrie on
(Melds with Graf Rats.) Mirrorwing Dragon Rarity: Mythic Rare TYPE: Creature SUBTYPE: Dragon CMC: 5 Mana cost: USD: $0.53 EUR: 0.44 TIX: 0.03 EDHREC RANK: 8267 (4/5) Flying Whenever a player casts an instant or sorcery spell that targets only this creature, that player copies that spell for each other creature they control that the spell could target
Personally speaking, the second option to flicker a nonland permanent is the best ability among the three