Siege Modification

Enchant creature or Vehicle
As long as enchanted permanent is a Vehicle, it's a creature in addition to its other types.
Enchanted creature gets +3/+0 and has first strike.

Consulate Dreadnought

Crew 6 (Tap any number of creatures you control with total power 6 or more: This Vehicle becomes an artifact creature until end of turn.)

Veteran Motorist

When Veteran Motorist enters, scry 2.
Whenever Veteran Motorist crews a Vehicle, that Vehicle gets +1/+1 until end of turn.

Hotshot Mechanic

Hotshot Mechanic crews Vehicles as though its power were 2 greater.

Mizzium Tank

Trample
Whenever you cast a noncreature spell, Mizzium Tank becomes an artifact creature and gets +1/+1 until end of turn.
Crew 1 (Tap any number of creatures you control with total power 1 or more: This Vehicle becomes an artifact creature until end of turn.)

Magda, Brazen Outlaw

Other Dwarves you control get +1/+0.
Whenever a Dwarf you control becomes tapped, create a Treasure token.
Sacrifice five Treasures: Search your library for an artifact or Dragon card, put that card onto the battlefield, then shuffle.

Assault Strobe

Target creature gains double strike until end of turn. (It deals both first-strike and regular combat damage.)

Smuggler's Copter

Flying
Whenever Smuggler's Copter attacks or blocks, you may draw a card. If you do, discard a card.
Crew 1 (Tap any number of creatures you control with total power 1 or more: This Vehicle becomes an artifact creature until end of turn.)

Speedway Fanatic

Haste
Whenever Speedway Fanatic crews a Vehicle, that Vehicle gains haste until end of turn.

Fleetwheel Cruiser

Trample, haste
When Fleetwheel Cruiser enters, it becomes an artifact creature until end of turn.
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.)

Reckoner Bankbuster

Reckoner Bankbuster enters with three charge counters on it.
{2}, {T}, Remove a charge counter from Reckoner Bankbuster: Draw a card. Then if there are no charge counters on Reckoner Bankbuster, create a Treasure token and a 1/1 colorless Pilot creature token with "This creature crews Vehicles as though its power were 2 greater."
Crew 3

Depala, Pilot Exemplar

Other Dwarves you control get +1/+1.
Each Vehicle you control gets +1/+1 as long as it's a creature.
Whenever Depala, Pilot Exemplar becomes tapped, you may pay {X}. If you do, reveal the top X cards of your library, put all Dwarf and Vehicle cards from among them into your hand, then put the rest on the bottom of your library in a random order.

Sram, Senior Edificer

Whenever you cast an Aura, Equipment, or Vehicle spell, draw a card.

Born to Drive

Enchant artifact or creature
As long as enchanted permanent is a creature, it gets +1/+1 for each creature and/or Vehicle you control.
Channel — {2}{W}, Discard Born to Drive: Create two 1/1 colorless Pilot creature tokens with "This creature crews Vehicles as though its power were 2 greater."