MechaPilot
Explorer
So another question is, what unrevealed races will be given playable status? I assume that hobgoblins and kobolds will as well, given that they are classic D&D humanoids. And since tritons will need someone to adventure with underwater, I assume merfolk will become playable and we'll see aquatic elves detailed in the book.
If I had to guess, I'd say aquatic elves but no merfolk. There's a tendency in creature design to just slap an environmental adjective on an elf instead of doing the actual work of detailing something else.