Card

Marwyn, the Nurturer

Mana cost {2}{G}

Whenever another Elf you control enters, put a +1/+1 counter on Marwyn. {T}: Add an amount of {G} equal to Marwyn's power.

Part of 69 known combos, 5 of them two-card. 1 official ruling.

Bracket

B1 Exhibition — Not in the same deck as its two-card combo partners: Staff of Domination, Umbral Mantle, Sword of the Paruns, Ringing Strike Mastery, Singing Bell Strike
B2 Core — Not in the same deck as its two-card combo partners: Staff of Domination, Umbral Mantle, Sword of the Paruns, Ringing Strike Mastery, Singing Bell Strike
B3 Upgraded — Not in the same deck as its early two-card combo partners: Staff of Domination, Umbral Mantle, Sword of the Paruns, Ringing Strike Mastery, Singing Bell Strike
B4 Optimized — allowed: No restriction beyond the banned list
B5 cEDH — allowed: No restriction beyond the banned list

Two-card combo with Staff of Domination, Umbral Mantle, Sword of the Paruns, Ringing Strike Mastery, Singing Bell Strike (early with Staff of Domination, Umbral Mantle, Sword of the Paruns, Ringing Strike Mastery, Singing Bell Strike)

Bracket: Lotus Vault analysis, with Commander Spellbook flags

69 known combos, 5 of them two-card.

Staff of Domination + Marwyn, the Nurturer
Produces: Infinite card draw, Infinite draw triggers, Infinite lifegain
View on Commander Spellbook
Umbral Mantle + Marwyn, the Nurturer
Produces: Infinite green mana, Infinitely large creature until end of turn, Infinite untap of creatures you control
View on Commander Spellbook
Sword of the Paruns + Marwyn, the Nurturer
Produces: Infinite mana creatures you control can produce, Infinite untap of creatures you control, Infinite green mana
View on Commander Spellbook

2018-04-27 · Wizards of the Coast
Marwyn's activated ability is a mana ability. It doesn't use the stack and can't be responded to.

Rulings: Scryfall · Wizards of the Coast