Barbarian Ring

{T}: Add {R}. Barbarian Ring deals 1 damage to you.
Threshold — {R}, {T}, Sacrifice Barbarian Ring: It deals 2 damage to any target. Activate only if seven or more cards are in your graveyard.

Modern Horizons 3

The List

Premium Deck Series: Fire and Lightning

{T}: Add {R} to your mana pool. Barbarian Ring deals 1 damage to you.
Threshold — {R}, {T}, Sacrifice Barbarian Ring: Barbarian Ring deals 2 damage to target creature or player. Activate this ability only if seven or more cards are in your graveyard.

Odyssey

oc
T: Add o
R to your mana pool. Barbarian Ring deals 1 damage to you.
Threshold o
R, oc
T, Sacrifice Barbarian Ring: Barbarian Ring deals 2 damage to target creature or player. (Play this ability only if seven or more cards are in your graveyard.)