Eagles of the North

Flying
When this creature enters, creatures you control get +1/+0 and gain first strike until end of turn.
Plainscycling {1} ({1}, Discard this card: Search your library for a Plains card, reveal it, put it into your hand, then shuffle.)

Commander's Sphere

{T}: Add one mana of any color in your commander's color identity.
Sacrifice this artifact: Draw a card.

Generous Gift

Destroy target permanent. Its controller creates a 3/3 green Elephant creature token.

Cabaretti Courtyard

When this land enters, sacrifice it. When you do, search your library for a basic Mountain, Forest, or Plains card, put it onto the battlefield tapped, then shuffle and you gain 1 life.

Shadowfax, Lord of Horses

Horses you control have haste. (They can attack and {T} as soon as they come under your control.)
Whenever Shadowfax attacks, you may put a creature card with lesser power from your hand onto the battlefield tapped and attacking.

Rapacious Dragon

Flying
When this creature enters, create two Treasure tokens. (They're artifacts with "{T}, Sacrifice this token: Add one mana of any color.")

Command Tower

{T}: Add one mana of any color in your commander's color identity.

Now for Wrath, Now for Ruin!

Put a +1/+1 counter on each creature you control. They gain vigilance until end of turn. The Ring tempts you.

Arcane Signet

Oliphaunt

Trample
Whenever this creature attacks, another target creature you control gets +2/+0 and gains trample until end of turn.
Mountaincycling {1} ({1}, Discard this card: Search your library for a Mountain card, reveal it, put it into your hand, then shuffle.)