Elves and Half-Elves have the Fey Ancestry trait, which states
You have advantage on saving throws against being charmed.
What spells and effects are covered by this? Only Charm Person? Enchantment spells with a Wis save?
A good answer should contain either rule text and/or official or unofficial statements (tweets) by the 5e design team.
Charmed is a specific game condition. From Appendix A of the PHB (page 290):
Charmed
- A charmed creature can’t attack the charmer or target the charmer with harmful abilities or magical effects.
- The charmer has advantage on any ability check to interact socially with the creature.
So Fey Ancestry gives advantage on any saving throw to avoid receiving the Charmed condition. Or to put it differently, a creature with Fey Ancestry has advantage on any saving throw made to avoid the effect of a spell, trap, or other effect that inflicts the Charmed condition.
Fey Ancestry will give you advantage on saving throws against any spell, ability or device that would impose the Charmed condition on a failed save.
Since spells are the most frequent way of getting the Charmed condition, I thought I might pull out a list of the spells that would trigger Fey Ancestry (PHB, p. 211-289) :
There are a few more spells that impose the Charmed condition, but they don't trigger Fey Ancestry because they can't target humanoids (Animal Friendship, Awaken and Dominate Beast).
Some monsters have specific actions that also trigger Fey Ancestry. Here they are, with the name of the relevant ability :
Of course, some other creatures can cast spells included in the list up above, thus triggering Fey Ancestry.
If a spell or ability would charm the character or creature with Fey Ancestry and if the spell or ability allows a saving throw to avoid the effects, the character or creature with Fey Ancestry gets advantage on that saving throw.
One example is the spell Crown of Madness, which reads:
One humanoid of your choice that you can see within range must succeed on a Wisdom saving throw or be Charmed by you for the duration.
Here's how it would work. Let's say we have an Elf character, because Elves have Fey Ancestry, and someone casts Crown of Madness on this Elf. The Elf has Advantage on the Wisdom Saving throw because the spell has a Charm effect.
Additionally, the Fey Ancestry feature reads (emphasis mine):
You have advantage on saving throws against being charmed, and magic can't put you to sleep.
If the spell or ability says it charms its targets, and if it offers a saving throw, the targets with Fey Ancestry get Advantage on such saving throws.
I hope this answer is to your satisfaction.
It provides advantage only against charmed condition Here is a tweet by the design team https://www.sageadvice.eu/does-fey-ancestry-apply-to-any-spell/
