Summary
Baldur’s Gate 3is built aroundDungeons & Dragons5th Edition, but that doesn’t mean that everything from this system is implemented into the game. More specifically, a whole lot of subclasses didn’t make the cut, as Baldur’s Gate 3 has 46 out of the 123 officially recognised options in 5e.
We’re getting 12 more in Patch 8, but that still leaves out a lot of subclasses that fans might have been hoping to see from the tabletop game. So, a fan is throwing together as many as possible, bringing together all of the various mods that add more 5e subclasses into Baldur’s Gate 3 throughDnD Master Class.

This Baldur’s Gate 3 Mod Lets You Access More Subclasses
The mod works by bringing together other mods that add 5e subclasses
“There are many good [Dungeons & Dragons] class and subclass mods on Nexus Mods, but due to how the game is coded, you can only load one subclass per class at a time,” says mod creator ImADoctorNotA. “My mod fixes this while ensuring the authors who made the subclasses get credit. My mod does not work unless you download their mods.”
So, you’ll need to download the original mods, but ImADoctorNotA’s files mean that you should be able to stack your save with a bunch of 5e subclasses that have been ported into Baldur’s Gate 3 by fans.

If you want to download everything at once, the modder has put all of the compatible subclasses into amod collectionfor ease of use.
As noted in the mod’s description, not every subclass has a mod yet, but more are being added. In fact, fans are always sharing new classes and subclasses,including some homebrew creations.
In any case, we’re getting some new subclasses in an official capacity very soon. Each class is getting a new one, and all come from 5e. Some will have access to them already through Patch 8 early access, but there is no launch date for its wider release just yet.