Card

Basalt Monolith

Mana cost {3}

This artifact doesn't untap during your untap step. {T}: Add {C}{C}{C}. {3}: Untap this artifact.

Part of 301 known combos, 12 of them two-card. 1 official ruling.

Bracket

B1 Exhibition — Not in the same deck as its two-card combo partners: Forsaken Monument, Rings of Brighthearth, Kinnan, Bonder Prodigy, Forensic Gadgeteer, Nyxbloom Ancient, Power Artifact, Zirda, the Dawnwaker, Mesmeric Orb, Mana Reflection, The Enigma Jewel // Locus of Enlightenment, Crackdown Construct, Wake Thrasher
B2 Core — Not in the same deck as its two-card combo partners: Forsaken Monument, Rings of Brighthearth, Kinnan, Bonder Prodigy, Forensic Gadgeteer, Nyxbloom Ancient, Power Artifact, Zirda, the Dawnwaker, Mesmeric Orb, Mana Reflection, The Enigma Jewel // Locus of Enlightenment, Crackdown Construct, Wake Thrasher
B3 Upgraded — Not in the same deck as its early two-card combo partners: Forsaken Monument, Rings of Brighthearth, Kinnan, Bonder Prodigy, Forensic Gadgeteer, Nyxbloom Ancient, Power Artifact, Zirda, the Dawnwaker, Mesmeric Orb, Mana Reflection, The Enigma Jewel // Locus of Enlightenment, Crackdown Construct, Wake Thrasher
B4 Optimized — allowed: No restriction beyond the banned list
B5 cEDH — allowed: No restriction beyond the banned list

Two-card combo with Forsaken Monument, Rings of Brighthearth, Kinnan, Bonder Prodigy, Forensic Gadgeteer, Nyxbloom Ancient, Power Artifact, Zirda, the Dawnwaker, Mesmeric Orb, Mana Reflection, The Enigma Jewel // Locus of Enlightenment, Crackdown Construct, Wake Thrasher (early with Forsaken Monument, Rings of Brighthearth, Kinnan, Bonder Prodigy, Forensic Gadgeteer, Nyxbloom Ancient, Power Artifact, Zirda, the Dawnwaker, Mesmeric Orb, Mana Reflection, The Enigma Jewel // Locus of Enlightenment, Crackdown Construct, Wake Thrasher)

Bracket: Lotus Vault analysis, with Commander Spellbook flags

301 known combos, 12 of them two-card.

2020-08-07 · Wizards of the Coast
Basalt Monolith's last ability can untap it as often as you can pay for it. If you believe you've found a way to generate an unbounded amount of mana with it, you're probably right.

Rulings: Scryfall · Wizards of the Coast