Ultimate Adventurer's Handbook
Mage Barrier
3-level Abjuration
Casting Time: 1 reaction, which you take when you fail a saving throw against a spell
Range/Area: Self
Components: V, S
Duration: 1 round
A shining barrier of magical force appears and protects you, reducing the harmful effects of certain spells cast on you. Until the start of your next turn, you have a +5 bonus to saving throws against spells, including against the triggering spell. For the duration, when you are subjected to a spell that allows you to make a saving throw to take only half damage, you instead take no damage if you succeed on the saving throw, and only half damage if you fail.