From the moment they arrived, wedding guests were met with a pageant of wealth and excess.

Welcoming Vampire

Flying
Whenever one or more other creatures you control with power 2 or less enter, draw a card. This ability triggers only once each turn.

Innistrad: Crimson Vow Promos

Murders at Karlov Manor Commander

Flying
Whenever one or more other creatures with power 2 or less enter the battlefield under your control, draw a card. This ability triggers only once each turn.

The Lost Caverns of Ixalan Commander

Innistrad: Double Feature

If creatures enter the battlefield with +1/+1 counters or a continuous effect such as that of Wedding Festivity will apply to the creatures on the battlefield, those effects apply when checking to see if Welcoming Vampire's ability will trigger.

Welcoming Vampire's ability checks the power of the other creatures only as they enter the battlefield. If one of those creatures has power 2 or less, the ability will trigger. Once the ability triggers, raising that creature's power above 2 won't affect that ability. Similarly, reducing a creature's power to 2 or less after it enters the battlefield won't cause the ability to trigger.