April O'Neil, Live on the Scene {1}{U}
Legendary Creature — Human Detective
BlueCommander: legal
Identity
Blue
EDHREC rank
#10,710
Cheapest printing
US$0.24
TCGplayer
Printings
3
Whenever a Mutant, Ninja, or Turtle you control enters, investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this token: Draw a card.")
Partner—Character select
Keywords: investigate, partner
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.