Plains

Forest

Arcane Signet

{T}: Add one mana of any color in your commander's color identity.

The Ur-Dragon

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.

Sol Ring

Island

Rhystic Study

Whenever an opponent casts a spell, you may draw a card unless that player pays {1}.