Thunder Brute

Trample
Tribute 3 (As this creature enters, an opponent of your choice may put three +1/+1 counters on it.)
When Thunder Brute enters, if tribute wasn't paid, it gains haste until end of turn.

Nessian Demolok

Tribute 3 (As this creature enters, an opponent of your choice may put three +1/+1 counters on it.)
When Nessian Demolok enters, if tribute wasn't paid, destroy target noncreature permanent.

Shrike Harpy

Flying
Tribute 2 (As this creature enters, an opponent of your choice may put two +1/+1 counters on it.)
When Shrike Harpy enters, if tribute wasn't paid, target opponent sacrifices a creature of their choice.

Ornitharch

Flying
Tribute 2 (As this creature enters, an opponent of your choice may put two +1/+1 counters on it.)
When Ornitharch enters, if tribute wasn't paid, create two 1/1 white Bird creature tokens with flying.

Snake of the Golden Grove

Tribute 3 (As this creature enters, an opponent of your choice may put three +1/+1 counters on it.)
When Snake of the Golden Grove enters, if tribute wasn't paid, you gain 4 life.

Flame-Wreathed Phoenix

Flying
Tribute 2 (As this creature enters, an opponent of your choice may put two +1/+1 counters on it.)
When Flame-Wreathed Phoenix enters, if tribute wasn't paid, it gains haste and "When this creature dies, return it to its owner's hand."

Oracle of Bones

Haste
Tribute 2 (As this creature enters, an opponent of your choice may put two +1/+1 counters on it.)
When Oracle of Bones enters, if tribute wasn't paid, you may cast an instant or sorcery spell from your hand without paying its mana cost.

Nessian Wilds Ravager

Tribute 6 (As this creature enters, an opponent of your choice may put six +1/+1 counters on it.)
When Nessian Wilds Ravager enters, if tribute wasn't paid, you may have Nessian Wilds Ravager fight another target creature. (Each deals damage equal to its power to the other.)

Siren of the Fanged Coast

Flying
Tribute 3 (As this creature enters, an opponent of your choice may put three +1/+1 counters on it.)
When Siren of the Fanged Coast enters, if tribute wasn't paid, gain control of target creature.

Pharagax Giant

Tribute 2 (As this creature enters, an opponent of your choice may put two +1/+1 counters on it.)
When Pharagax Giant enters, if tribute wasn't paid, Pharagax Giant deals 5 damage to each opponent.

Fanatic of Xenagos

Trample
Tribute 1 (As this creature enters, an opponent of your choice may put a +1/+1 counter on it.)
When Fanatic of Xenagos enters, if tribute wasn't paid, it gets +1/+1 and gains haste until end of turn.