Roar of Challenge

All creatures able to block target creature this turn do so.
Ferocious — That creature gains indestructible until end of turn if you control a creature with power 4 or greater.

Barrage of Boulders

Barrage of Boulders deals 1 damage to each creature you don't control.
Ferocious — If you control a creature with power 4 or greater, creatures can't block this turn.

Bonders' Enclave

{T}: Add {C}.
{3}, {T}: Draw a card. Activate only if you control a creature with power 4 or greater.

Flamewake Phoenix

Flying, haste
This creature attacks each combat if able.
At the beginning of combat on your turn, if you control a creature with power 4 or greater, you may pay {R}. If you do, return this card from your graveyard to the battlefield.

Strider, Ranger of the North

Landfall — Whenever a land you control enters, target creature gets +1/+1 until end of turn. Then if that creature has power 4 or greater, it gains first strike until end of turn.

Boundary Lands Ranger

At the beginning of combat on your turn, if you control a creature with power 4 or greater, you may discard a card. If you do, draw a card.

Entish Restoration

Sacrifice a land. Search your library for up to two basic land cards, put them onto the battlefield tapped, then shuffle. If you control a creature with power 4 or greater, instead search your library for up to three basic land cards, put them onto the battlefield tapped, then shuffle.

Challenger Troll

Each creature you control with power 4 or greater can't be blocked by more than one creature.

Goreclaw, Terror of Qal Sisma

Creature spells you cast with power 4 or greater cost {2} less to cast.
Whenever Goreclaw, Terror of Qal Sisma attacks, each creature you control with power 4 or greater gets +1/+1 and gains trample until end of turn.

Colossal Majesty

At the beginning of your upkeep, if you control a creature with power 4 or greater, draw a card.

Bolt Bend

This spell costs {3} less to cast if you control a creature with power 4 or greater.
Change the target of target spell or ability with a single target.

Drowsing Tyrannodon

Defender (This creature can't attack.)
As long as you control a creature with power 4 or greater, Drowsing Tyrannodon can attack as though it didn't have defender.

Rhonas the Indomitable

Deathtouch, indestructible
Rhonas the Indomitable can't attack or block unless you control another creature with power 4 or greater.
{2}{G}: Another target creature gets +2/+0 and gains trample until end of turn.

Dragon Grip

Ferocious — If you control a creature with power 4 or greater, you may cast Dragon Grip as though it had flash. (You may cast it any time you could cast an instant.)
Enchant creature
Enchanted creature gets +2/+0 and has first strike.

Force Away

Return target creature to its owner's hand.
Ferocious — If you control a creature with power 4 or greater, you may draw a card. If you do, discard a card.

Crater's Claws

Crater's Claws deals X damage to any target.
Ferocious — Crater's Claws deals X plus 2 damage instead if you control a creature with power 4 or greater.

Anax, Hardened in the Forge

Anax's power is equal to your devotion to red. (Each {R} in the mana costs of permanents you control counts toward your devotion to red.)
Whenever Anax or another nontoken creature you control dies, create a 1/1 red Satyr creature token with "This creature can't block." If the creature had power 4 or greater, create two of those tokens instead.