The Ur-Dragon {4}{W}{U}{B}{R}{G}
Legendary Creature — Dragon Avatar
Identity
Five-color
EDHREC rank
#2,669
Cheapest printing
US$34.63
TCGplayer
Printings
7
Eminence — As long as The Ur-Dragon is in the command zone or on the battlefield, other Dragon spells you cast cost {1} less to cast.
Flying
Whenever one or more Dragons you control attack, draw that many cards, then you may put a permanent card from your hand onto the battlefield.
Every printing
highest TCGplayer market first; a card with only a thin single listing shows its low
Textured Foil
The Ur-Dragon
CMM · 1065
TCGplayer market
US$231.61
Foil Etched
The Ur-Dragon
CMM · 594
TCGplayer market
US$66.24
Secret Lair
The Ur-Dragon
SLD · 11
TCGplayer market
US$60.17
Borderless
The Ur-Dragon
CMM · 689
TCGplayer market
US$51.89
The Ur-Dragon
C17 · 48
TCGplayer market
US$37.01
The Ur-Dragon
CMM · 361
TCGplayer market
US$35.53
Future Sight
The Ur-Dragon
PF25 · 15
TCGplayer market
US$34.63
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.