Karn, Scion of Urza Hour of Devastation {1}{R}: Dragons you control get

{1}{R}: Dragons you control get +1/+0 until end of turn

They also serve as a great way to store a sideboard or cards together

made from 2 mm of natural rubber

Enchant creature

exile up to one other target nonland permanent

Karn, Scion of Urza Hour of Devastation {1}{R}: Dragons you control get+1: Reveal the top two cards of your library. An opponent chooses one of them. Put that card into your hand and exile the other with a silver counter on it. 1: Put a card you own with a silver counter on it from exile into your hand. 2: Create a 0 0 colorless Construct artifact creature token with "This token gets +1 +1 for each artifact you control."