Peppermint Tea...
"Does peppermint tea have caffeine? Unless blended with ingredients that contain caffeine, peppermint tea is caffeine free. However, it may still be the perfect choice for increasing the alertness without taking caffeinated drinks. Research says that peppermint may increase alertness and improve memory"
Source: https://www.healthline.com/nutrition/top-10-evidence-based-health-benefits-of-green-tea