Takes time to control due to the risk of the ability could accidentally destroy items the users didn't mean to destroy.
Noble metals are resistant to acids.
May have a limit on how much acid that can be produce.
May have a limit on what kinds of acids user can produce.
Magellan (One Piece); technically a poison-user, but one of his poisons behaves more like acid.
Terumī Mei/Fifth Mizukage (Naruto); can produce a kind of vapor that is corrosive
Lily (Code: Breaker)
Gluttony (FullMetal Alchemist); acidic saliva
Preta Ghoul (Black Cat)
Hendrickson (Nanatsu no Taizai)
Agony (Marvel Comics)
Scorpion (Marvel Comics)
David Haller/Legion (Marvel Comics); via Personality 762
Anarchist (Marvel Comics); could sweat acid and fire acid blasts from his hands.
Man-Thing (Marvel Comics); uncertain whether the acidic burn caused by his powers is mystical or biochemical. Stated in some comics to be "sulfuric acid" though it has been shown to burn even those with superhuman durability.
David North/Agent Zero (Marvel Comics)
James Natale/Vulture (Marvel Comics)
Artilas (Geneforge series)
Roamers (Geneforge Series)
The Freaks (Crackdown 2)
Spitter (Left 4 Dead 2)
Reptile (Mortal Kombat Series)
Hazmat (Marvel Nemesis: Rise of the Imperfects)
Viron.Volkov (Storm of the Imperial Sanctum)
Subterran.Unix (Storm of the Imperial Sanctum)
Joseph Bertrand III (Infamous 2)
The Xenomorphs (Aliens); some variants can spit acidic saliva, while all variants blood highly acidic blood.
Yukio Fusou (DDD)
Saibamen (Dragon Ball Z)
Kat (Kid vs Kat)
Keelerak (BIONICLE); Rhotuka spinner power
The Vulture/Jimmy Natale (Marvel Comics)
The Bahrag queens (BIONICLE)
Goop (Ben 10: Alien Force)
Acid Breath (Ben 10)
Scabbar Demons (Charmed)
Karen Young (Charmed); was used by power brokers to hold this power