Livio, Oathsworn Sentinel {1}{W}
Legendary Creature — Human Knight
WhiteCommander: legal
Identity
White
EDHREC rank
#20,386
Cheapest printing
US$0.24
TCGplayer
Printings
2
{1}{W}: Choose another target creature. Its controller may exile it with an aegis counter on it.
{2}{W}, {T}: Return all exiled cards with aegis counters on them to the battlefield under their owners' 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.