Trained Arynx

Whenever this creature attacks while saddled, it gains first strike until end of turn. Scry 1. (Look at the top card of your library. You may put that card on the bottom.)
Saddle 2 (Tap any number of other creatures you control with total power 2 or more: This Mount becomes saddled until end of turn. Saddle only as a sorcery.)

Alacrian Jaguar

Vigilance
Whenever this creature attacks while saddled, it gets +2/+2 until end of turn.
Saddle 1 (Tap any number of other creatures you control with total power 1 or more: This Mount becomes saddled until end of turn. Saddle only as a sorcery.)

Interface Ace

This creature saddles Mounts and crews Vehicles using its toughness rather than its power.
Whenever this creature becomes tapped during your turn, untap it. This ability triggers only once each turn.

Brightfield Glider

Vigilance
Whenever this creature attacks while saddled, it gets +1/+2 and gains flying until end of turn.
Saddle 3 (Tap any number of other creatures you control with total power 3 or more: This Mount becomes saddled until end of turn. Saddle only as a sorcery.)

Avishkar Raceway

Start your engines! (If you have no speed, it starts at 1. It increases once on each of your turns when an opponent loses life. Max speed is 4.)
{T}: Add {C}.
Max speed — {3}, {T}, Discard a card: Draw a card.

Steer Clear

Steer Clear deals 2 damage to target attacking or blocking creature. Steer Clear deals 4 damage to that creature instead if you controlled a Mount as you cast this spell.

Forest

Guidelight Matrix

When this artifact enters, draw a card.
{2}, {T}: Target Mount you control becomes saddled until end of turn. Activate only as a sorcery.
{2}, {T}: Target Vehicle you control becomes an artifact creature until end of turn.

Throw from the Saddle

Target creature you control gets +1/+1 until end of turn. Put a +1/+1 counter on it instead if it's a Mount. Then it deals damage equal to its power to target creature you don't control.

Lightwheel Enhancements

Enchant creature or Vehicle
Start your engines! (If you have no speed, it starts at 1. It increases once on each of your turns when an opponent loses life. Max speed is 4.)
Enchanted permanent gets +1/+1 and has vigilance.
Max speed — You may cast this card from your graveyard.

Giant Beaver

Vigilance
Whenever this creature attacks while saddled, put a +1/+1 counter on target creature that saddled it this turn.
Saddle 3 (Tap any number of other creatures you control with total power 3 or more: This Mount becomes saddled until end of turn. Saddle only as a sorcery.)

Run Over

This spell costs {1} less to cast if it targets a Mount or Vehicle you control.
Target creature you control deals damage equal to its power to target creature an opponent controls.

Drover Grizzly

Whenever this creature attacks while saddled, creatures you control gain trample until end of turn.
Saddle 1 (Tap any number of other creatures you control with total power 1 or more: This Mount becomes saddled until end of turn. Saddle only as a sorcery.)

Brightfield Mustang

Whenever this creature attacks while saddled, untap it and put a +1/+1 counter on it.
Saddle 1 (Tap any number of other creatures you control with total power 1 or more: This Mount becomes saddled until end of turn. Saddle only as a sorcery.)

Leonin Surveyor

Start your engines! (If you have no speed, it starts at 1. It increases once on each of your turns when an opponent loses life. Max speed is 4.)
During your turn, this creature has first strike.
Max speed — {3}, Exile this card from your graveyard: Draw a card.

Compassionate Healer

Whenever this creature becomes tapped, you gain 1 life and scry 1. (Look at the top card of your library. You may put it on the bottom.)