Activate Tortured Existence by paying {B} and discarding a creature card.
Green Goblin's first ability triggers, putting a +1/+1 counter on Crystalline Crawler.
Resolve the Tortured Existence ability, returning another creature card from your graveyard to your hand.
Activate Crystalline Crawler's first ability by removing a +1/+1 counter from it, adding {B}.
Repeat.

Infinite self-discard triggers

Green Goblin, Nemesis

Tortured Existence

Crystalline Crawler

Stalactite Dagger

Activate Tortured Existence by paying {B} and discarding Dryad Arbor.
Green Goblin's second ability triggers, creating two tapped Treasure tokens.
When the Treasures enters the battlefield, Amulet of Vigor triggers twice, untapping the Treasures.
Resolve the Tortured Existence ability, returning another creature card from your graveyard to your hand.
Activate two Treasures by tapping and sacrificing them, adding {B}{B}.
Activate Tortured Existence by paying {B} and discarding a creature card.
Green Goblin's first ability triggers, putting a +1/+1 counter on a Goblin you control.
Resolve the Tortured Existence ability, returning Dryad Arbor from your graveyard to your hand.
Repeat.

Infinite +1/+1 counters on Goblins you control

Dryad Arbor

Amulet of Vigor

Xorn

Activate Tortured Existence by paying {B} and discarding Dryad Arbor.
Green Goblin's second ability triggers, creating a tapped Treasure token.
When the Treasure enters the battlefield, Amulet of Vigor triggers, untapping the Treasure.
Resolve the Tortured Existence ability, returning another creature card from your graveyard to your hand.
Activate the Treasure by tapping and sacrificing it, adding {B}{B}.
Activate Tortured Existence by paying {B} and discarding a creature card.
Green Goblin's first ability triggers, putting a +1/+1 counter on a Goblin you control.
Resolve the Tortured Existence ability, returning Dryad Arbor from your graveyard to your hand.
Repeat.

Goldspan Dragon

Activate Tortured Existence by paying {B} and discarding Dryad Arbor.
Green Goblin's second ability triggers, creating an untapped Treasure token due to Archelos.
Resolve the Tortured Existence ability, returning another creature card from your graveyard to your hand.
Activate the Treasure by tapping and sacrificing it, adding {B}{B}.
Activate Tortured Existence by paying {B} and discarding a creature card.
Green Goblin's first ability triggers, putting a +1/+1 counter on a Goblin you control.
Resolve the Tortured Existence ability, returning Dryad Arbor from your graveyard to your hand.
Repeat.

Archelos, Lagoon Mystic

Activate Tortured Existence by paying {B} and discarding Dryad Arbor.
Green Goblin's second ability triggers, creating two untapped Treasure tokens due to Archelos.
Resolve the Tortured Existence ability, returning another creature card from your graveyard to your hand.
Activate two Treasures by tapping and sacrificing them, adding {B}{B}.
Activate Tortured Existence by paying {B} and discarding a creature card.
Green Goblin's first ability triggers, putting a +1/+1 counter on a Goblin you control.
Resolve the Tortured Existence ability, returning Dryad Arbor from your graveyard to your hand.
Repeat.

Combos with "Green Goblin, Nemesis"