Trance (5e Feat)
From D&D Wiki
Prerequisites: Must have an Elven parent or be the Monk class.
You don’t need to sleep. Instead, you meditate deeply, remaining semiconscious, for 4 hours a day. (The Common word for such meditation is “trance.”) While meditating, you can still dream; 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 person normally gets from 8 hours of sleep.