These are the cards which, no matter what strategy is chosen, are necessary to make Niv successful
The amount of power that youre getting for three mana is pretty insane with Gideon of the Trials
You want to get a big legend into your graveyard, reanimate it with the titular instant, and ride that huge value wave to victory
Due to already having the green mana to make the Elf means tapping for just colourless is about as good as you can get and should mean the card outperforms not just other mana elves but also things like Birds of Paradise because of the fixing

Akoum Firebird Amethyst Dragon Amethyst Dragon Archwing Dragon Arclight Phoenix Artistic Process Bloodfeather Phoenix Bloodsworn Steward Bogardan Dragonheart Brimstone Dragon Cam and Farrik, Havoc Duo Cavern-Hoard Dragon Chandra's Phoenix Chaos Dragon Chiss-Goria, Forge Tyrant Conquering Manticore Detective's Phoenix Draconautics Engineer Draconic Destiny Dracosaur Auxiliary Dragon Tempest Dragonwing Glider Emissary of Grudges Experimental Armor Falkenrath Marauders Flame-Wreathed Phoenix Flamewake Phoenix Furygale Flocking Galvanizing Sawship Glorybringer Goddric, Cloaked Reveler Goldnight Castigator Goldspan Dragon Goro-Goro, Disciple of Ryusei Harried Dronesmith Hell's Thunder Hellkite Charger Hellkite Courser Hellkite Igniter Hobgoblin, Mantled Marauder Human Torch Hunted Dragon Impetuous Sunchaser Inferno of the Star Mounts Jack of Hearts, Volatile Hero Jaya's Phoenix Khorvath Brightflame Kuldotha Phoenix Lightning Phoenix Lightning Shrieker Living Lightning, Charged Up Loyal Apprentice Magda, the Hoardmaster Manaform Hellkite Mizzix, Replica Rider Nalfeshnee Nova Hellkite Ore-Scale Guardian Phoenix Chick Phoenix of Ash Predator Dragon Pyreswipe Hawk Realm-Scorcher Hellkite Rekindling Phoenix Retriever Phoenix Rorix Bladewing Sarkhan, the Dragonspeaker Shivan Branch-Burner Shivan Devastator Skarrgan Hellkite Skyfire Phoenix Skyship Stalker
