Related to this question, what forms of damage affect an Unseen Servant?
- Physical types: bludgeoning, piercing, slashing.
- Magical forms of the physical types.
- The other types, some of which are always magical, while others can be magical or mundane in nature:
Acid, Fire, Cold, Poison, Necrotic, Radiant, Lightning, Psychic, Thunder and Force.
- Falling damage (a special type of bludgeoning, related to this question).
- As a "mindless" entity, it makes sense a Servant cannot take psychic damage.
- Acid, Fire, Cold, Lightning, and physical damage hinge on whether the Servant has a "body" or not (see the first link).
- Poison seems like a no, as the Servant certainly doesn't breathe and has no means of absorbing the poison.
- Necrotic and Radiant are harder to define, as those damage types are themselves open to interpretation.
- Thunder seems like a no, as it has no hard body to damage with vibrations and doesn't appear capable of hearing anything.
- Force seems like a yes.
- Fall damage is highly dependent on the answer to the second link.
- Since a Servant cannot move through objects like spectral creatures, it seems unlikely a magical weapon would be any different than a regular weapon.