Here is the puzzle: It's not a product, but a technology. And it's unexpected. What might it be?

Elon Musk's tweet from Sunday confirms that there will be no new product unveilings in the near future: "Cybertruck is our last product unveil for a while", which is reasonable as besides the Model S, Model X and Model 3, Tesla has 4 models in the pipeline:

We also know that customers are waiting for the Solar Roof, new Megapack energy storage systems and rollout of V3 Supercharging network (250 kW).

At the same time, Elon hints at upcoming "technology announcements", which mostly will be unexpected:

"Cybertruck is our last product unveil for a while, but there will be some (mostly) unexpected technology announcements next year"

 

We already know that Tesla is working on its own in-house battery cell technology that would provide higher energy density/more affordable prices, which is not an unexpected then.

The question is what else does Tesla have on its shelves that we mostly do not expect?