Card

Seedborn Muse

Mana cost {3}{G}{G}

Untap all permanents you control during each other player's untap step.

Game Changer: not allowed in brackets 1–2, counts as one of the three allowed in bracket 3. Part of 7 known combos. 2 official rulings.

Commander: Legal
Game Changer: On the official list — none allowed in brackets 1–2, at most three in bracket 3.
Printing: Rare · LGN · #138
Cheapest printing: €9.75
EDHREC salt: 1.77
Color identity: Green

Bracket

B1 Exhibition — not allowed: Game Changers are not allowed
B2 Core — not allowed: Game Changers are not allowed
B3 Upgraded — counts toward 3 Game Changers: Counts toward the 3 Game Changers allowed
B4 Optimized — allowed: No restriction beyond the banned list
B5 cEDH — allowed: No restriction beyond the banned list

Bracket: Lotus Vault analysis, with Commander Spellbook flags

7 known combos.

2007-07-15 · Wizards of the Coast
All your permanents untap during each other player's untap step. You have no choice about what untaps.
2004-10-04 · Wizards of the Coast
Other effects can prevent a permanent from untapping during an untap step. You do need to look carefully, however, as many effects say that the permanent does not untap during its controller's untap step, and this card's ability occurs during other players' untap steps. If a card does say this, then Seedborn Muse can untap it. But some other abilities are not written this way and can still prevent a card from untapping.

Rulings: Scryfall · Wizards of the Coast