Green Goblin

Flying, menace
Spells you cast from your graveyard cost {2} less to cast.
Goblin Formula — Each nonland card in your graveyard has mayhem. The mayhem cost is equal to its mana cost. (You may cast a card from your graveyard for its mayhem cost if you discarded it this turn. Timing rules still apply.)

Norman Osborn

Norman Osborn can't be blocked.
Whenever Norman Osborn deals combat damage to a player, he connives. (Draw a card, then discard a card. If you discarded a nonland card, put a +1/+1 counter on this creature.)
{1}{U}{B}{R}: Transform Norman Osborn. Activate only as a sorcery.

Norman Osborn // Green Goblin

Swamp

Command Tower

{T}: Add one mana of any color in your commander's color identity.

Mountain

Arcane Signet

Green Goblin, Nemesis

Flying
Whenever you discard a nonland card, put a +1/+1 counter on target Goblin you control.
Whenever you discard a land card, create a tapped Treasure token.

Ultimate Green Goblin

At the beginning of your upkeep, discard a card, then create a Treasure token.
Mayhem {2}{B/R} (You may cast this card from your graveyard for {2}{B/R} if you discarded it this turn. Timing rules still apply.)

Sol Ring

Green Goblin, Revenant

Flying, deathtouch
Whenever Green Goblin attacks, discard a card. Then draw a card for each card you've discarded this turn.