Elementalist

Elemental Burn
Beginning at 8th level, you develop an understanding for the most fundamental elements of destructive magic. Whenever you cast a spell that deals Acid, Cold, Fire, or Lightning damage, you can choose to deal any of those four damage types. Additionally, as a bonus action, you may conjure four dormant elemental runes in the air around you, one corresponding to each of these four damage types. When you cast a spell that deals the associated elemental damage type and damages at least one creature, one of these runes activates. When all four are active, you may expend them all as a free action when casting a spell in order to apply any one metamagic effect to it for free. If not used before then, these glyphs vanish after one minute.

Memorize
Beginning at 13th level, unleashing the most basic manifestations of the elements is no more taxing than flexing your muscles or taking a breath. Whenever you cast a spell of at least 1st level that deals acid, cold, fire, or lightning damage and damages at least one creature, you can Quicken a cantrip of that element without expending any sorcery points before the end of the current turn (even if you do not normally know the Quicken metamagic). Additionally, you gain the Widen metamagic. When you cast a spell that has a Cone, Cube, Sphere, or Cylinder area of effect, you can pay 2 sorcery points to increase the size of that area by 50%, rounded down to the nearest multiple of 5'.

Magic Festival
Beginning at 18th level, when you cast a spell of 5th level or lower that deals acid, cold, fire, or lightning damage and is not a Concentration spell, you can choose to maintain concentration on it for up to one minute. If you do so, you can recast the spell once on each round you maintain concentration without expending any SP. A recast spell does not automatically gain any metamagic applied to the initial casting, and is cast using the default action for casting the spell in question. You may apply metamagic to these additional castings normally, and must cast the spell as a different element each time. If you have already cast the spell with all four elements, your concentration automatically ends.