Scion of the Ur-Dragon {W}{U}{B}{R}{G}
Legendary Creature — Dragon Avatar
Identity
Five-color
EDHREC rank
#5,983
Cheapest printing
US$7.88
TCGplayer
Printings
3
Flying
{2}: Search your library for a Dragon permanent card and put it into your graveyard. If you do, Scion of the Ur-Dragon becomes a copy of that card until end of turn. Then shuffle.
Keywords: flying
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.