Is Arcus Acolyte legal in Standard, Modern, and Commander?

Arcus Acolyte is legal in: Modern, Legacy, Vintage, Commander, Historic.

What type of card is Arcus Acolyte?

Arcus Acolyte is a Creature — Human Cleric Archer. Its oracle text reads: "Reach, lifelink Outlast {G/W} ({G/W}, {T}: Put a +1/+1 counter on this creature. Outlast only as a sorcery.) Each other creature you control without a +1/+1 counter on it has outlast {G/W}."