Elemental Damage Types
Elemental Damage Types are a long-running and proud tradition of tabletop gaming, even if some may now think they were a vidya invention. Similarly to Physical Damage Types, Elemental Damage Types let RPGs broaden the tactical aspect of combat by giving creatures unique resistances, weaknesses and immunities - a fiery creature is typically resistant to fire but vulnerable to cold, or vice versa, though breaking the paradigm can and does happen, which players can often be rather ticked off by.
In D&D
Dungeons & Dragons, of course, has long used elemental damage types, though ironically it has never managed to perfectly equate its use of them with its elementalism, instead tending to have Acid stand in for Earth, Cold for Water, and Lightning for Fire.
Acid: Corrodes and melts things.
Cold: Freezes things. In older editions, creatures killed by cold damage may freeze solid and then shatter, resulting in losing their loot.
Fire: Burns things.
Lightning: Zaps things.
Sonic: Pulverizes flesh and shatters bones with waves of sonic force. Introduced in 3rd edition, it was renamed to the more fantastical-sounding Thunder damage type in 4th, and this stuck around into 5th edition.
Positive Energy: Draws upon the energy of life itself. Most Positive Energy effects only hurt the undead and instead heal the living, under the old "Revive Kills Zombie" trope.
Negative Energy: Draws upon the shadowy energies of death to drain away life. In a reverse to Positive Energy (they are even drawn from opposite Energy Planes), Negative Energy tends to heal the undead and harm the living.
Radiant: Disintegrates things with the elemental powers of light. Aka, lasers! Introduced in 4th edition as a more fantasy-appropriate alternative to Positive Energy, and stuck around into 5e.
Necrotic: Dissolves things into darkness and dust with the elemental power of nothingness. Introduced in 4th edition as a more fantasy-appropriate alternative to Negative Energy, and stuck around into 5e.
[[Poison: Whethere or not Poison is an elemental damage type has flip-flopped over the years, but it seemed to solidify as one with 4th and 5th edition.