Crested Sunmare

Other Horses you control have indestructible.
At the beginning of each end step, if you gained life this turn, create a 5/5 white Horse creature token.

Brightling

{W}: Brightling gains vigilance until end of turn.
{W}: Brightling gains lifelink until end of turn.
{W}: Return Brightling to its owner's hand.
{1}: Brightling gets +1/-1 or -1/+1 until end of turn.

Sol Ring

Fire Diamond

Fire Diamond enters tapped.
{T}: Add {R}.

Arcane Signet

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

Plains

Command Tower

Path of Ancestry

Path of Ancestry enters tapped.
{T}: Add one mana of any color in your commander's color identity. When that mana is spent to cast a creature spell that shares a creature type with your commander, scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Lightning Mare

This spell can't be countered.
Lightning Mare can't be blocked by blue creatures.
{1}{R}: Lightning Mare gets +1/+0 until end of turn.

Shadowfax, Lord of Horses

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

Keleth, Sunmane Familiar

Whenever a commander you control attacks, put a +1/+1 counter on it.
Partner (You can have two commanders if both have partner.)