Defender

When Akroan Horse enters the battlefield, an opponent gains control of it.

At the beginning of your upkeep, each opponent creates a 1/1 white Soldier creature token.

When Bill the Pony enters the battlefield, create two Food tokens. (They're artifacts with "{2}, {T}, Sacrifice this artifact: You gain 3 life.")

Sacrifice a Food: Until end of turn, target creature you control assigns combat damage equal to its toughness rather than its power.

Trample

As long as you control another creature, prevent all damage that would be dealt to Bronze Horse by spells that target it.

Metalcraft -- Chrome Steed gets +2/+2 as long as you control three or more artifacts.

Clockwork Steed enters the battlefield with four +1/+0 counters on it.

Clockwork Steed can't be blocked by artifact creatures.

At end of combat, if Clockwork Steed attacked or blocked this combat, remove a +1/+0 counter from it.

{X}, {T}: Put up to X +1/+0 counters on Clockwork Steed. This ability can't cause the total number of +1/+0 counters on Clockwork Steed to be greater than four. Activate only during your upkeep.

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.

As Diamond Mare enters the battlefield, choose a color.

Whenever you cast a spell of the chosen color, you gain 1 life.

{1}{R}, {T}: Target Dwarf creature gains mountainwalk until end of turn. (It can't be blocked as long as defending player controls a Mountain.)

{2}, {T}: Untap target attacking creature you control. Prevent all combat damage that would be dealt to and dealt by that creature this turn.

Hipparion can't block creatures with power 3 or greater unless you pay {1}.

Whenever a commander you control attacks, put a +1/+1 counter on it.

Partner (You can have two commanders if both have partner.)

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.

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.

Shield Mare can't be blocked by red creatures.

When Shield Mare enters the battlefield or becomes the target of a spell or ability an opponent controls, you gain 3 life.

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)

I -- Create a 1/1 white Human Noble creature token with vanishing 3 and "Prevent all damage that would be dealt to this creature."

II -- Create a 2/2 white Horse creature token with "Doctors you control have horsemanship." (They can't be blocked except by creatures with horsemanship.)

III -- Whenever a creature you control deals combat damage to a player this turn, time travel.

Haste (This creature can attack and {T} as soon as it comes under your control.)

When Thundermare enters the battlefield, tap all other creatures.

Sacrifice a land: Trenching Steed gets +0/+3 until end of turn.

Workhorse enters the battlefield with four +1/+1 counters on it.

Remove a +1/+1 counter from Workhorse: Add {C}.