Master of Etherium

Mana cost: {2}{U}
Type: Artifact Creature — Vedalken Wizard
Power / toughness: * / *
Set: March of the Machine Commander #226 (rare)
Price: $0.62 USD

Master of Etherium's power and toughness are each equal to the number of artifacts you control.
Other artifact creatures you control get +1/+1.

Master of Etherium has 10 printings, first in Shards of Alara (2008). EDHREC ranks it #2,111 among Commander cards. It appears most in Urza, Chief Artificer decks (9,690 on EDHREC). 5 public decks on TCG run it. It has 3 official rulings.

Legality

commander: legal
legacy: legal
vintage: legal
pauper: not legal
modern: legal
pioneer: not legal
standard: not legal
brawl: not legal

Public decks that run Master of Etherium

Buckle Up - Neon Dynasty Commander, led by Kotori, Pilot Prodigy
Invent Superiority - Commander 2016, led by Breya, Etherium Shaper
Keen Engineering - Foundations Commander, led by Sai, Master Thopterist
Tinker Time - March of the Machine Commander, led by Gimbal, Gremlin Prodigy
Urza's Iron Alliance - The Brothers' War Commander, led by Urza, Chief Artificer

Commanders that run Master of Etherium most

Deck counts from EDHREC.

Often played with Master of Etherium

Cards that show up in the same decks on EDHREC.

Rulings

2020-08-07: Because damage remains marked on a creature until the damage is removed as the turn ends, nonlethal damage dealt to Master of Etherium may become lethal if other artifacts you control leave the battlefield during that turn, and damage dealt to other artifact creatures you control may become lethal if Master of Etherium leaves the battlefield during that turn.
2020-08-07: The ability that defines Master of Etherium's power and toughness applies in all zones, not just the battlefield.
2020-08-07: As long as Master of Etherium is on the battlefield, its ability will count itself.