Glaciers

At the beginning of your upkeep, sacrifice Glaciers unless you pay {W}{U}.
All Mountains are Plains.

Healer's Hawk

Flying
Lifelink (Damage dealt by this creature also causes you to gain that much life.)

Wings of Hope

Enchant creature
Enchanted creature gets +1/+3 and has flying.

Staggering Insight

Enchant creature
Enchanted creature gets +1/+1 and has lifelink and "Whenever this creature deals combat damage to a player, draw a card."

Wings of Aesthir

Enchant creature
Enchanted creature gets +1/+0 and has flying and first strike.

Gregor, Shrewd Magistrate

Skulk (This creature can't be blocked by creatures with greater power.)
Whenever Gregor, Shrewd Magistrate deals combat damage to a player, draw cards equal to its power.