Loremaster | Pillars of Eternity 2 Wiki

 Conjurer

 Bonus: Gain +1 Power Level with Conjuration Spells.
Gain "Conjure Familiar" spell: Summons a helpful creature to aid the wizard. Familiars are poor at combat, but provide passive bonuses to their master.

 Penalty: Lose access to spells from Evocation and Illusion schools.
+20% Recovery Time for Wizard Spells not of the Conjuration School.

Enchanter

 Bonus: +1 Power Level with Enchanting Spells.
Gain "Free Action" passive: Once per encounter, when the wizard is affected by a Dexterity Affliction, they will clear that effect and become temporarily immune to Dexterity Afflictions.

 Penalty: Lose access to spells from Illusion and Transmutation schools.
+20% Recovery Time for Wizard Spells not of the Enchanting School.

  Transmuter

 Bonus: +1 Power Level with Transmutation Spells.
Gain "Form of the Fearsome Brute" spell: Transforms the wizard into an Ogre. While in this form, spells are disabled, but physical attributes are increased.

 Penalty: Lose access to spells from Enchanting and Evocation schools.
+20% Recovery Time for Wizard Spells not of the Transmutation School.

  Evoker

 Bonus: +1 Power Level with Evocation Spells.
Your evocation spells have a small chance to "echo", reapplying their damage and effects to their targets again, instantly.

 Penalty: Lose access to spells from Transmutation and Conjuration schools.
+20% Recovery Time for Wizard Spells not of the Evocation School.

  Illusionist

 Bonus: +1 Power Level with Illusion Spells.
Gain "Reflexive Mirror" passive: Once per encounter, when first attacked, automatically gain the effects of the spell "Mirrored Images".

 Penalty: Lose access to spells from Conjuration and Enchanting schools.
+20% Recovery Time for Wizard Spells not of the Illusion School.

Beckoner

Bonus: All Invocations will summon twice the original number of creatures. Summon Invocations cost 1 Phrase less.
Creatures from all Invocations become immune to the Abjurationability of Paladins (who could otherwise destroy any creature that is their level, and deal raw damage to any equal or greater level creature)

Penalty: The chanter's summons are smaller and have reduced Health and Duration.

Skald

Bonus: Offensive Invocations have reduced cost of -1 Phrase. Weapon Critical Hits have a 50% chance to grant +1 Phrase.

Penalty: Non-Offensive Invocations have an increased cost of +1 Phrase.

Troubadour

Bonus: Linger for Phrases is increased significantly (this means that as one phrase ends and another starts, they overlap for a little while giving both effects). 
Gain "Brisk Recitation" (Modal Abilities) that increases the rate that phrases elapse, but removes the linger. 

Penalty: All Invocations have an increased cast cost of +1 Phrase (Chant)