Mental Agility (5e Feat)
From D&D Wiki
Prerequisites: Intelligence 13 or greater
Your Mental Agility increases your Intelligence score by 1.
Due to your mental agility you can concentrate on an additional discipline, spell or magical effect.
Concentrating on more than one discipline, spell, or magical effect can only be maintained for a maximum of 10 minutes divided up into increments no smaller than 1 minute. After you use the whole 10 minutes, you regain the ability to do so after a long rest.