Doran, Besieged by Time

Each creature spell you cast with toughness greater than its power costs {1} less to cast.
Whenever a creature you control attacks or blocks, it gets +X/+X until end of turn, where X is the difference between its power and toughness.

Last March of the Ents

This spell can't be countered.
Draw cards equal to the greatest toughness among creatures you control, then put any number of creature cards from your hand onto the battlefield.

Doran, the Siege Tower

Each creature assigns combat damage equal to its toughness rather than its power.

Timber Protector

Other Treefolk creatures you control get +1/+1.
Other Treefolk and Forests you control have indestructible.

Betor, Kin to All

Flying
At the beginning of your end step, if creatures you control have total toughness 10 or greater, draw a card. Then if creatures you control have total toughness 20 or greater, untap each creature you control. Then if creatures you control have total toughness 40 or greater, each opponent loses half their life, rounded up.

Brave the Sands

Creatures you control have vigilance.
Each creature you control can block an additional creature each combat.

Huatli, the Sun's Heart

Each creature you control assigns combat damage equal to its toughness rather than its power.
−3: You gain life equal to the greatest toughness among creatures you control.

Selvala, Heart of the Wilds

Whenever another creature enters, its controller may draw a card if its power is greater than each other creature's power.
{G}, {T}: Add X mana in any combination of colors, where X is the greatest power among creatures you control.

Slaughter the Strong

Each player chooses any number of creatures they control with total power 4 or less, then sacrifices all other creatures they control.