Card

Pili-Pala

Mana cost {2}

Flying {2}, {Q}: Add one mana of any color. ({Q} is the untap symbol.)

Part of 303 known combos, 3 of them two-card. 4 official rulings.

Bracket

B1 Exhibition — Not in the same deck as its two-card combo partners: Grand Architect, Careful Cultivation, Bigger on the Inside
B2 Core — Not in the same deck as its two-card combo partners: Grand Architect, Careful Cultivation, Bigger on the Inside
B3 Upgraded — Not in the same deck as its early two-card combo partners: Grand Architect, Careful Cultivation, Bigger on the Inside
B4 Optimized — allowed: No restriction beyond the banned list
B5 cEDH — allowed: No restriction beyond the banned list

Two-card combo with Grand Architect, Careful Cultivation, Bigger on the Inside (early with Grand Architect, Careful Cultivation, Bigger on the Inside)

Bracket: Lotus Vault analysis, with Commander Spellbook flags

303 known combos, 3 of them two-card.

2008-05-01 · Wizards of the Coast
Pili-Pala’s ability is a mana ability. It doesn’t use the stack and can’t be responded to.
2008-05-01 · Wizards of the Coast
Using this creature’s ability means you’re untapping it for mana, not tapping it for mana. Mana Reflection won’t cause it to produce extra mana.
2008-05-01 · Wizards of the Coast
If Pili-Pala is already untapped, you can’t activate its {Q} ability. That’s because you can’t pay the “Untap this permanent” cost.
2008-05-01 · Wizards of the Coast
If a creature with an {Q} ability hasn’t been under your control since your most recent turn began, you can’t activate that ability, unless the creature has haste.

Rulings: Scryfall · Wizards of the Coast