Padeem, Consul of Innovation

Mana cost: {3}{U}
Type: Legendary Creature — Vedalken Artificer
Power / toughness: 1 / 4
Set: Kaladesh Promos #59p (rare)
Price: $11.55 USD

Artifacts you control have hexproof. (They can't be the targets of spells or abilities your opponents control.)
At the beginning of your upkeep, if you control the artifact with the greatest mana value or tied for the greatest mana value, draw a card.

Padeem, Consul of Innovation has 8 printings, first in Kaladesh (2016). EDHREC ranks it #894 among Commander cards. It appears most in Breya, Etherium Shaper decks (9,359 on EDHREC). 2 public decks on TCG run it. It has 4 official rulings.

Legality

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

Public decks that run Padeem, Consul of Innovation

Keen Engineering - Foundations Commander, led by Sai, Master Thopterist
Mishra's Burnished Banner - The Brothers' War Commander, led by Mishra, Eminent One

Commanders that run Padeem, Consul of Innovation most

Deck counts from EDHREC.

Breya, Etherium Shaper: 9,359 decks
Urza, Chief Artificer: 8,778 decks
Urza, Lord High Artificer: 7,897 decks
Dr. Eggman: 7,743 decks
Aloy, Savior of Meridian: 6,439 decks
Mishra, Eminent One: 5,141 decks
Urtet, Remnant of Memnarch: 4,615 decks
Tony Stark // The Invincible Iron Man: 4,605 decks

Often played with Padeem, Consul of Innovation

Cards that show up in the same decks on EDHREC.

Rulings

2016-09-20: If you no longer control an artifact with the highest mana value as Padeem's triggered ability resolves, you don't draw a card.
2016-09-20: The artifact you control has to have the highest mana value only among artifacts on the battlefield, not among all permanents on the battlefield.
2016-09-20: If you don't control an artifact with the highest mana value as your upkeep begins, Padeem's second ability won't trigger. You can't cast an instant to destroy an opponent's artifact during your turn before your upkeep begins.
2016-09-20: If an artifact has {X} in its mana cost, X is considered to be 0.