Spelldriver

Through intense focus, training, and dedication, you’ve harnessed the techniques of rapid spellcasting. When you use your bonus action to cast a spell of 1st level or higher, you can also use your action to cast another spell of 1st level or higher. However, if you cast two or more spells in a single turn, only one of them can be 3rd level or higher.

Rules Tip: Casting Multiple Spells
Normally, when you cast a spell as a bonus action, you can’t use your action to also cast a spell that turn unless that spell is a cantrip. The Spelldriver feat removes that restriction, but the focus necessary to channel multiple spells in the same round still limits the overall power of those spells.

- From Tal'Dorei Campaign Setting Reborn Book Page: 190