Sakashima of a Thousand Faces {3}{U}
Legendary Creature — Human Rogue
BlueCommander: legal
Identity
Blue
EDHREC rank
#1,074
Cheapest printing
US$19.12
TCGplayer
Printings
4
You may have Sakashima enter as a copy of another creature you control, except it has Sakashima's other abilities.
The "legend rule" doesn't apply to permanents you control.
Partner (You can have two commanders if both have partner.)
Keywords: 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.