Crytpo Currency: There is room for more disruption here. I suspect a currency that is both trackable and backed by a pool of commodities/currencies could be quite popular. Traceable would make theft risk reduced as money could effectively be returned if it is stolen and being backed/hedged by currencies/commodities would help with confidence.
Cargo: I'm surprised we haven't seen electric cargo ships. Even combine solar with sail as winds are favorable. This combined with auto-navigation (at least between ports) seems more easily achievable than cars yet technology is further behind.
Dockable Phone to PC (physical or even better if wireless dock): Surprised no-one has done this well yet. I can image whoever does this with really take ownership of the OS space. I always felt this could be the best route for Microsoft to re-enter the mobile space with force.