Avatar: The Last Airbender (TLA)

Firebending

The rule

Whenever this creature attacks, you add red mana (the number N shown); this mana lasts until end of combat.

In play

The mana only exists during combat: you have to attack to benefit, so the creatures that make it are first of all attackers.

The archetypes that lean on it

The other mechanics of the set

The Firebending cards, ranked

Ranked by win rate when the card is in hand (the cards with few games follow, by pick rating).