I want an open source cellular baseband chip. That's the chip that acts as a networking connection to cell phone towers. Not only would the drivers be open, but the hardware as well. It might be a little larger than most, as I would want it to be possible for users to dismantle it (destructively, of course) and verify against tampering.
Bunnie Huang's Precursor was a good start, but it lacks networking (as far as I know)
(Are crowdsourcing links allowed? I'm not going to link to the crowdsupply page, just in case, but it is more informative)