Arcanist

At 5th sorcerer level, learn 3 extra metamagic effects from the base list, and a further 1 extra at every subsequent Arcanist level.

At 5th sorcerer level, your MP maximum is increased by 3.

At 5th sorcerer level, when you use overcharge, you gain 1 temporary MP that can be used to apply metamagic to the overcharged spell. This MP is lost if it is not spent on the spell.

At 6th sorcerer level, choose 2 upgrades from the list below:

• Arcane overcharge - You gain 1 extra temporary MP more from overcharge metamagic.

• Ally spell manipulation - You can spend 1 MP as a reaction to apply a metamagic effect to a spell cast by an ally, spending the metamagics MP cost as they do. 

• Mastered metamagic - Choose 2 metamagic effects that you can apply. Reduce their cost by 1, down to a minimum of 1. Choose a 3rd effect to reduce in cost at 8th sorcerer level.

• MP enervation - You can spend 1 rest dice to regain 1d4 (min 2) MP as a bonus action.

• Forced spell manipulation - You can spend 4 MP or 1 rest dice as a reaction to apply a metamagic effects to a spell targeting you or a creature or area within 20ft of you.

• Blood sorcery - You can spend 1d4 HP to gain 1 temporary MP that must be used until the start of your next turn, or it will be lost. This can be done as a free action. The health cost cannot be reduced below 1. 

• Arcana disruption - You can spend 4 MP to attempt to dispel an ongoing spell, magical ability, or curse within 30ft with an arcana check.

• Metacast arcana - You can spend 3 MP or 1 rest dice to reduce the casting time of a spell from an action to a bonus action.

• Cantrip manipulation - Upgrade a cantrip or hex you know twice. Your MP maximum is increased by 1.

At 7th sorcerer level you can choose to lock one spell known, cantrip, or spell you can cast during a rest. Doing so locks the spell or cantrip from use until you finish another rest. The MP cost for all metamagic effects belonging to any school of the locked spell or cantrip are reduced by 1(min 0). 

At 8th sorcerer level, learn 3 special metamagics from the list below. They belong to no school.

• Ring of wrath (3) - Cast a cone spell in a ring around you at the original range.

• Twin spell (4) - Cast two of the spell at once, at no increased slot cost. The targets and areas of the spell cannot overlap.

• Sniper spell (2) - Double the range of a spell.

• stable spell (4) - Cause a concentration spell to lose the concentration component.

• Horde spell (4) - Cause a summon spell to summon 1 more creature.

• Power spell (3) - Increase the damage dice of the spell by 1 size category.

• upgraded cantrip (1) - Upgrade a cantrip when casting it.

• willed spell (2) - The spell requires no verbal or somatic components.