Give Ancient Adamantoise indestructible by any method.
Cast Arcbond by paying {2}{R}, targeting Ancient Adamantoise
Deal damage to yourself or a permanent you control, with that damage being redirected to Ancient Adamantoise
Arcbond triggers, dealing damage equal to the damage dealt to Ancient Adamantoise to each other creature and each player, with all damage that would be dealt to you and creatures you control being dealt to Ancient Adamantoise instead.
Repeat from step 4.

Infinite damage

Ancient Adamantoise

Arcbond

If you haven't cast Derevi from the command zone this game, cast it by paying {G}{W}{U}. Otherwise, activate Derevi by paying {1}{G}{W}{U}, putting it from the command zone onto the battlefield.
Derevi enters the battlefield as a copy of Ancient Adamantoise due to Infinite Reflection. When it enters, Blasting Station triggers, untapping Blasting Station.
Activate Blasting Station by tapping it and sacrificing Derevi.
Choose to return Derevi from your graveyard to the command zone.
When Derevi dies, it triggers, creating ten tapped Treasure tokens.
When the Treasures enter the battlefield, Amulet of Vigor triggers that many times, untapping the Treasures.
Resolve the Blasting Station ability.
Activate four Treasures by tapping and sacrificing them, adding {1}{G}{W}{U}.
Repeat.

Infinite artifact ETB

Infinite artifact LTB

Infinite artifact sacrifice triggers

Infinite artifact tokens

Infinite creature LTB

Infinite creature ETB

Infinite colored mana

Infinite creature sacrifice triggers

Infinite death triggers

Infinite Treasure tokens

Derevi, Empyrial Tactician

Infinite Reflection

Amulet of Vigor

Blasting Station

Activate Spawning Pit by sacrificing Ancient Adamantoise.
When Ancient Adamantoise dies, it and Nim Deathmantle trigger.
Resolve the Nim Deathmantle trigger, causing you to pay {4} to return Ancient Adamantoise from your graveyard to the battlefield and attach Nim Deathmantle to it.
Resolve the Ancient Adamantoise trigger, creating ten tapped Treasure tokens.
Resolve the Spawning Pit ability.
Activate Krark-Clan Ironworks twice by sacrificing two Treasures, adding {C}{C}{C}{C}.
Repeat.

Infinite charge counters on a permanent

Infinite colorless mana

Infinite creature tokens

Infinite tapped Treasure tokens

Nim Deathmantle

Krark-Clan Ironworks

Spawning Pit

Activate Phyrexian Altar by sacrificing Ancient Adamantoise, adding one mana of any color.
When Ancient Adamantoise dies, it and Nim Deathmantle trigger.
Resolve the Nim Deathmantle trigger, causing you to pay {4} to return Ancient Adamantoise from your graveyard to the battlefield and attach Nim Deathmantle to it.
Resolve the Ancient Adamantoise trigger, creating ten tapped Treasure tokens.
When the Treasures enter, Amulet of Vigor triggers ten times, untapping the Treasures.
Activate three Treasures by tapping and sacrificing them, adding {3}.
Repeat.

Phyrexian Altar

Activate Umbral Collar Zealot by sacrificing Ancient Adamantoise.
When Ancient Adamantoise dies, it triggers.
Holding priority, activate Gravewaker by paying {5}{B}{B}, returning Ancient Adamantoise from your graveyard to the battlefield.
Resolve the Ancient Adamantoise trigger, creating ten tapped Treasure tokens.
When the Treasures enter, Amulet of Vigor triggers ten times, untapping the Treasures.
Resolve the Umbral Collar Zealot ability.
Activate seven Treasures by tapping and sacrificing them, adding {5}{B}{B}.
Repeat.

Infinite surveil

Gravewaker

Umbral Collar Zealot

Activate Phyrexian Altar by sacrificing Ancient Adamantoise, adding {W}.
When Ancient Adamantoise dies, it and Sword of the Realms trigger.
Resolve the Sword of the Realms trigger, returning Ancient Adamantoise from your graveyard to your hand.
Resolve the Ancient Adamantoise trigger, creating ten tapped Treasure tokens.
When the Treasures enter, Amulet of Vigor triggers ten times, untapping the Treasures.
Activate nine Treasures by tapping and sacrificing them, adding {6}{G}{G}{G}.
Cast Ancient Adamantoise by paying {5}{G}{G}{G}.
Activate Sword of the Realms by paying {1}{W}, attaching it to Ancient Adamantoise.
Repeat.

Infinite storm count

Halvar, God of Battle // Sword of the Realms

Activate Phyrexian Altar by sacrificing Ancient Adamantoise, adding {G}.
When Ancient Adamantoise dies, it and Enduring Renewal trigger.
Resolve the Enduring Renewal trigger, returning Ancient Adamantoise from your graveyard to your hand.
Resolve the Ancient Adamantoise trigger, creating ten tapped Treasure tokens.
When the Treasures enter, Amulet of Vigor triggers ten times, untapping the Treasures.
Activate seven Treasures by tapping and sacrificing them, adding {5}{G}{G}.
Cast Ancient Adamantoise by paying {5}{G}{G}{G}.
Repeat.

Enduring Renewal

Combos with "Ancient Adamantoise"