There was this one shot villain back in the early/mid 90's. Byrne era of Superman, I believe.
Her power was that anything she says the name of, explodes. Street lights, signs, building, anything. Turned out she wasn't even real, just an involuntary construct of an innocent woman, which implies an insane amount of latent power.
Looked everywhere for a name, but apparently she's no obscure, she's not on any list.