Nahiri, Forged in Fury (Showcase) [March of the Machine: The Aftermath] Angel and you may spend mana

and you may spend mana as though it were mana of any color to cast spells this way

up to one target creature gets -3/-0

Set: Guildpact Type: Creature — Boar Beast Rarity: Uncommon Cost: {2}{G} Bloodthirst 1 (If an opponent was dealt damage this turn

Set: Zendikar Type: Artifact — Equipment Rarity: Rare Cost: {1} Whenever a creature dies

You may cast it without paying its mana cost if it's a spell with lesser mana value

Nahiri, Forged in Fury (Showcase) [March of the Machine: The Aftermath] Angel and you may spend manaSet: March of the Machine: The Aftermath Type: Legendary Creature Kor Artificer Rarity: Mythic Cost: {4}{R}{W} Affinity for Equipment (This spell costs 1 less to cast for each Equipment you control.) Whenever an equipped creature you control attacks, exile the top card of your library. You may play that card this turn. You may cast Equipment spells this way without paying their mana costs.