Optical Processors, FGPA 'reconfigurable hardware', 3d layering, Quantum processors (if they ever go commercial), Neurochips (rat-brain-neural-network-on-a-chip for specialist hardware applications). If hardware devs ever run out of ideas we may even have to go back to resource-efficient programming!
Next couple of generations will still be "shrinking stuff", after that it will be "new stuff" (e.g. graphene) and "stacking stuff" (3D integration).
Specialization. We're already seeing specialized processors take over niches of compute (Googles TPU, bitcoin ASICs, GPUs etc etc). I think we'll see this trend accelerate.