Aid

Source: Player's Handbook
  2nd-level abjuration
  Casting Time: 1 action Range: 30 feet Components: V, S, M (a tiny strip of white cloth) Duration: 8 hours
  Your spell bolsters your allies with toughness and resolve. Choose up to three creatures within range. Each target’s hit point maximum and current hit points increase by 5 for the duration.
  At Higher Levels. When you cast this spell using a spell slot of 3rd level or higher, a target’s hit points increase by an additional 5 for each slot level above 2nd.
  Spell Lists. Artificer, Bard, Cleric, Paladin, Ranger