Adrenaline Rusher (5e Feat)
From D&D Wiki
You activate your survival defense mechanism and push beyond your normal limits, causing you to become faster. On your turn, you can trigger a rush of adrenaline within yourself (no action required). You can take one additional action, and your movement speed increases by 15 feet until the end of your turn. Once you have used this feat, you can't use it again until you finish a short or long rest.