Urza's Saga

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I — Urza's Saga gains "{T}: Add {C}."
II — Urza's Saga gains "{2}, {T}: Create a 0/0 colorless Construct artifact creature token with 'This creature gets +1/+1 for each artifact you control.'"
III — Search your library for an artifact card with mana cost {0} or {1}, put it onto the battlefield, then shuffle.

Lotus Petal

{T}, Sacrifice Lotus Petal: Add one mana of any color.

Imposter Mech

You may have Imposter Mech enter as a copy of a creature an opponent controls, except it's a Vehicle artifact with crew 3 and it loses all other card types.
Crew 3

Sunhome, Fortress of the Legion

{T}: Add {C}.
{2}{R}{W}, {T}: Target creature gains double strike until end of turn.

Ancient Tomb

{T}: Add {C}{C}. Ancient Tomb deals 2 damage to you.

Enthusiastic Mechanaut

Flying
Artifact spells you cast cost {1} less to cast.

Foundry Inspector

Artifact spells you cast cost {1} less to cast.

Scalding Tarn

{T}, Pay 1 life, Sacrifice Scalding Tarn: Search your library for an Island or Mountain card, put it onto the battlefield, then shuffle.

Etherium Sculptor

Mobilizer Mech

Flying
Whenever Mobilizer Mech becomes crewed, up to one other target Vehicle you control becomes an artifact creature until end of turn.
Crew 3 (Tap any number of creatures you control with total power 3 or more: This Vehicle becomes an artifact creature until end of turn.)

Honeymoon Hearse

Trample
Tap two untapped creatures you control: Honeymoon Hearse becomes an artifact creature until end of turn.

Mox Opal

Metalcraft — {T}: Add one mana of any color. Activate only if you control three or more artifacts.

Plateau

Academy Ruins

{T}: Add {C}.
{1}{U}, {T}: Put target artifact card from your graveyard on top of your library.

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.)

Darksteel Forge

Artifacts you control have indestructible. (Effects that say "destroy" don't destroy them. Artifact creatures with indestructible can't be destroyed by damage.)

Jhoira, Weatherlight Captain

Whenever you cast a historic spell, draw a card. (Artifacts, legendaries, and Sagas are historic.)

Abrade

Choose one —
• Abrade deals 3 damage to target creature.
• Destroy target artifact.

Volcanic Island

Tundra

Chief Engineer

Artifact spells you cast have convoke. (Your creatures can help cast those spells. Each creature you tap while casting an artifact spell pays for {1} or one mana of that creature's color.)

Optimus Prime, Autobot Leader

Living metal (During your turn, this Vehicle is also a creature.)
Trample
Whenever you attack, bolster 2. The chosen creature gains trample until end of turn. When that creature deals combat damage to a player this turn, convert Optimus Prime.

Optimus Prime, Hero

More Than Meets the Eye {2}{U}{R}{W} (You may cast this card converted for {2}{U}{R}{W}.)
At the beginning of each end step, bolster 1. (Choose a creature with the least toughness among creatures you control and put a +1/+1 counter on it.)
When Optimus Prime dies, return it to the battlefield converted under its owner's control.