Mobile Homestead

Mobile Homestead has haste as long as you control a Mount.
Whenever Mobile Homestead attacks, look at the top card of your library. If it's a land card, you may put it onto the battlefield tapped.
Crew 2 (Tap any number of creatures you control with total power 2 or more: This Vehicle becomes an artifact creature until end of turn.)

Love Song of Night and Day

Read ahead (Choose a chapter and start with that many lore counters. Add one after your draw step. Skipped chapters don't trigger. Sacrifice after III.)
I — You and target opponent each draw two cards.
II — Create a 1/1 white Bird creature token with flying.
III — Put a +1/+1 counter on each of up to two target creatures.

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.

Plains

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.

Bridled Bighorn

Vigilance
Whenever Bridled Bighorn attacks while saddled, create a 1/1 white Sheep creature token.
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.)

Take Up the Shield

Put a +1/+1 counter on target creature. It gains lifelink and indestructible until end of turn. (Damage and effects that say "destroy" don't destroy it.)

Blossoming Sands

This land enters tapped.
When this land enters, you gain 1 life.
{T}: Add {G} or {W}.

Intrepid Stablemaster

Reach
{T}: Add {G}.
{T}: Add two mana of any one color. Spend this mana only to cast Mount or Vehicle spells.

Radiant Grove

({T}: Add {G} or {W}.)
Radiant Grove enters tapped.

Botanical Brawler

Trample
Botanical Brawler enters with two +1/+1 counters on it.
Whenever one or more +1/+1 counters are put on another permanent you control, if it's the first time +1/+1 counters have been put on that permanent this turn, put a +1/+1 counter on Botanical Brawler.

Drover Grizzly

Whenever Drover Grizzly 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.)

Bounding Felidar

Whenever Bounding Felidar attacks while saddled, put a +1/+1 counter on each other creature you control. You gain 1 life for each of those creatures.
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.)

Requisition Raid

Spree (Choose one or more additional costs.)
+ {1} — Destroy target artifact.
+ {1} — Destroy target enchantment.
+ {1} — Put a +1/+1 counter on each creature target player controls.

Miriam, Herd Whisperer

During your turn, Mounts and Vehicles you control have hexproof.
Whenever a Mount or Vehicle you control attacks, put a +1/+1 counter on it.

Forest

They Went This Way

Search your library for a basic land card, put it onto the battlefield tapped, then shuffle. Investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this artifact: Draw a card.")