The corrosive spray of a black dragon's breath and the dissolving enzymes secreted by a black pudding deal acid damage.
Bludgeoning
Blunt force attacks, falling, constriction, and the like deal bludgeoning damage.
Cold
The infernal chill radiating from an ice devil's spear and the frigid blast of a white dragon's breath deal cold damage.
Fire
Red dragons breathe fire, and many spells conjure flames to deal fire damage.
Force
Force is pure magical energy focused into a damaging form. Most effects that deal force damage are spells, including magic missile and spiritual weapon.
Lightning
A lightning bolt spell and a blue dragon's breath deal lightning damage.
Necrotic
Necrotic damage, dealt by certain undead and a spell such as chill touch, withers matter and even the soul.
Piercing
Puncturing and impaling attacks, including spears and monsters' bites, deal piercing damage.
Poison
Venomous stings and the toxic gas of a green dragon's breath deal poison damage.
Psychic
Mental abilities such as a psionic blast deal psychic damage.
Radiant
Radiant damage, dealt by a cleric's flame strike spell or an angel's smiting weapon, sears the flesh like fire and overloads the spirit with power.
Slashing
Swords, axes, and monsters' claws deal slashing damage.
Thunder
A concussive burst of sound, such as the effect of the thunderwave spell, deals thunder damage.