Card

Banishing Knack

Mana cost {U}

Until end of turn, target creature gains "{T}: Return target nonland permanent to its owner's hand."

Part of 81 known combos, 4 of them two-card. 2 official rulings.

Bracket

B1 Exhibition — Not in the same deck as its two-card combo partners: Sewer-veillance Cam, Intruder Alarm, Traxos, Scourge of Kroog, Zephyr Scribe
B2 Core — Not in the same deck as its two-card combo partners: Sewer-veillance Cam, Intruder Alarm, Traxos, Scourge of Kroog, Zephyr Scribe
B3 Upgraded — Not in the same deck as its early two-card combo partner: Intruder Alarm
B4 Optimized — allowed: No restriction beyond the banned list
B5 cEDH — allowed: No restriction beyond the banned list

Two-card combo with Sewer-veillance Cam, Intruder Alarm, Traxos, Scourge of Kroog, Zephyr Scribe (early with Intruder Alarm)

Bracket: Lotus Vault analysis, with Commander Spellbook flags

81 known combos, 4 of them two-card.

Valley Floodcaller + Banishing Knack
Produces: Infinite storm count, Infinite untap of some creatures you control, Infinite power and toughness for certain creatures until end of turn
View on Commander Spellbook
Valley Floodcaller + Banishing Knack + Sol Ring
Produces: Infinite storm count, Infinite untap of some creatures you control, Infinite power and toughness for certain creatures until end of turn
View on Commander Spellbook
Valley Floodcaller + Banishing Knack + Mana Vault
Produces: Infinite storm count, Infinite untap of some creatures you control, Infinite power and toughness for certain creatures until end of turn
View on Commander Spellbook

2008-08-01 · Wizards of the Coast
The targeted creature’s controller, not Banishing Knack’s controller, is the one who can activate the creature’s new ability.
2008-08-01 · Wizards of the Coast
“Summoning sickness” applies. The new ability can’t be activated unless the targeted creature has been under its controller’s control since the beginning of that player’s most recent turn or it has haste.

Rulings: Scryfall · Wizards of the Coast