Sol Ring

Arcane Signet

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

Mountain

Evereth, Viceroy of Plunder

Flying
Sacrifice another creature or artifact: Put a +1/+1 counter on Evereth, Viceroy of Plunder. If the sacrificed permanent was a Treasure, Evereth gains lifelink until end of turn. Activate only as a sorcery.
When Evereth dies, you may pay {1}{B/R}. When you do, Evereth deals damage equal to its power to each opponent.

Strefan, Maurer Progenitor

Flying
At the beginning of your end step, create a Blood token for each player who lost life this turn.
Whenever Strefan attacks, you may sacrifice two Blood tokens. If you do, you may put a Vampire card from your hand onto the battlefield tapped and attacking. It gains indestructible until end of turn.

Stensia Bloodhall

{T}: Add {C}.
{3}{B}{R}, {T}: Stensia Bloodhall deals 2 damage to target player or planeswalker.