Ancient Bronze Dragon

Flying
Whenever this creature deals combat damage to a player, roll a d20. When you do, put X +1/+1 counters on each of up to two target creatures, where X is the result.

Dragonbroods' Relic

{T}, Tap an untapped creature you control: Add one mana of any color.
{3}{W}{U}{B}{R}{G}, Sacrifice this artifact: Create a 4/4 Dragon creature token named Reliquary Dragon that's all colors. It has flying, lifelink, and "When this token enters, it deals 3 damage to any target." Activate only as a sorcery.

Sol Ring

Ancient Silver Dragon

Flying
Whenever this creature deals combat damage to a player, roll a d20. Draw cards equal to the result. You have no maximum hand size for the rest of the game.

Mountain

Arcane Signet

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

Ancient Gold Dragon

Flying
Whenever this creature deals combat damage to a player, roll a d20. You create a number of 1/1 blue Faerie Dragon creature tokens with flying equal to the result.

Ancient Brass Dragon

Flying
Whenever this creature deals combat damage to a player, roll a d20. When you do, put any number of target creature cards with total mana value X or less from graveyards onto the battlefield under your control, where X is the result.

Tiamat

Flying
When Tiamat enters, if you cast it, search your library for up to five Dragon cards not named Tiamat that each have different names, reveal them, put them into your hand, then shuffle.