Adric, Mathematical Genius {1}{U}
Legendary Creature — Human Artificer
BlueCommander: legal
Identity
Blue
EDHREC rank
#8,092
Cheapest printing
US$0.36
TCGplayer
Printings
4
{2}{U}, {T}: Copy target activated or triggered ability you control. You may choose new targets for the copy.
Ultimate Sacrifice — {1}{U}, Sacrifice Adric: Counter target activated or triggered ability.
Doctor's companion (You can have two commanders if the other is the Doctor.)
Keywords: ultimate sacrifice, doctor's companion
Every printing
highest TCGplayer market first; a card with only a thin single listing shows its low
In short
A Commander deck is a commander and 99 other cards, one copy of each (except basic lands), all inside the commander's colour identity. Paste a full list into the deck price calculator to price it and check it against the format.