Court Mage

Advisors are plentiful in a government's court, each with varying degrees of competency and use to the monarch or council. But one is nearly constant, especially in societies that have little experience in the ways of spells and such: The Court Mage. These wizards use their study of spells, creatures, and other magical phenomena to steer those they advise in a direction that is beneficial. Whether that's benefit to the kingdom or the mage is variable. 

Incantation Arcanum

At 2nd level, you learn a useful method of spell preparation that can give you an edge over your opponents on the battlefield, be it mortal combat or vicious debate. At the end of a long rest, when preparing your spells, you may choose a number of spells with a total level equal to half your wizard level. Until the end of your next long rest, you may cast the selected spells once without using verbal components, somatic components, or material components without a gold cost.

Courtly Experience

Starting at 2nd level, your knowledge of the ebb and flow of the political field gives you an edge when convincing someone. Choose either Persuasion or Deception. You can give yourself a bonus to rolls of this skill equal to your Intelligence modifier.

Deception

You may add your INT modifier to Deception checks.

Persuasion

You may add your INT modifier to Persuasion checks.

Mind Magic

Starting at 6th level, your careful study of magical manipulation allows you mastery over it.

You ignore class restrictions on enchantment school spells for the purposes of adding them to your spellbook or casting them from a scroll. In addition, you have advantage on saving throws against charm, frighten, and mind altering effects.

Mind Magic

You have advantage on saving throws made against charm, frighten, and other mind altering effects.

Plan B

Beginning at 10th level, even that act of shaking off some of your "diplomatic assistance" is mentally taxing. As a reaction, when a creature succeeds its saving throw against one of your enchantment spells, you may cause a backlash of energy. The creature takes psychic damage equal to 3d6 + you Intelligence modifier. You may choose if this damage is lethal or non-lethal.

Once you use this feature, you cannot do so again until you finish a short or long rest.

Arcane Renegotiation

At 14th level, you are experienced in turning a failure into a partial victory, both in court and in combat. When a creature succeeds on a saving throw against an enchantment spell you cast, you may use your reaction to roll an Intelligence check. The DC for this check is equal to 10 + the spell's level. On a success, you do not expend the spell slot the spell was cast with, but you take psychic damage equal to half your wizard level. 

Once you use this feature, you cannot use again until you finish a long rest.