Context:
Basically you attempt (so its not guaranteed to land) to use "attack" cards against other players or "heal" cards on yourself. But, if you're capped at full health and have a "heal" card instead of it being wasted it now allows you to guarantee 1 attack against any opponent.
So I am thematically trying to think of something that can be used as a heal and a direct attack depending on the situation.
One (mediocre) example is metal could be used to fortify a castle (heal) or create weapons (attack).
Do you have any ideas?