You know the Dancing Lights cantrip. When you reach 3rd level, you can cast the Faerie Fire spell once with this trait and regain the ability to do so when you finish a long rest. When you reach 5th level, you can cast the Darkness spell once with this trait and regain the ability to do so when you finish a long rest. Charisma is your spellcasting ability for these spells.
You have disadvantage on attack rolls and on Wisdom (Perception) checks that rely on sight when you, the target of your attack, or whatever you are trying to perceive is in direct sunlight.
Elves don't need to sleep. Instead, they meditate deeply, remaining semiconscious, for 4 hours a day. While meditating, you can dream after a fashion: such dreams are actually mental exercises that have become reflexive through years of practice. After resting in this way, you gain the same benefit that a human does from 8 hours of sleep.
You have advantage on saving throws against being charmed, and magic can't put you to sleep.
Accustomed to living underground, you have superior vision in the dark and dim conditions. You can see in dim light within 120 feet of you as if it were bright light, and in darkness as if it were dim light. You can't discern color in darkness, only shades of gray.