Confidence:StrongSolidPlausibleTentativeSpeculative

• Reanimate

  B

  SorceryB

  Reanimate puts Onyx Mage onto the battlefield from a graveyard without casting it, so its mana cost is never paid.
• Helping Hand

  W

  SorceryW

  Helping Hand puts Onyx Mage onto the battlefield from a graveyard without casting it, so its mana cost is never paid.
• Unearth

  B

  SorceryB

  Unearth puts Onyx Mage onto the battlefield from a graveyard without casting it, so its mana cost is never paid.
• Grave Researcher // Reanimate

  2BB

  Creature — Troll Warlock // SorceryB

  Grave Researcher puts Onyx Mage onto the battlefield from a graveyard without casting it, so its mana cost is never paid.
• Elrond, Moon-Reader

  2U

  Legendary Creature — Elf NobleU

  Onyx Mage has activated abilities that aren't mana abilities, fueling Elrond, Moon-Reader's activation-trigger.
• Goblin Sharpshooter

  2R

  Creature — GoblinR

  Lethal pinger: one card gives the other deathtouch, and the other is a pinger that untaps whenever a creature dies — so every ping kills a creature and readies it to ping again. It clears your opponents' creatures one by one, then stops when there is nothing left to kill (once, if the deathtouch only lasts the turn).
• Illusionist's Bracers

  2

  Artifact — EquipmentC

  Onyx Mage has activated abilities that aren't mana abilities, fueling Illusionist's Bracers's activation-trigger.
• Rings of Brighthearth

  3

  ArtifactC

  Onyx Mage has activated abilities that aren't mana abilities, fueling Rings of Brighthearth's activation-trigger.