To give you one example of a non-8 bit architecture, I used to work on CSR Bluetooth devices. For a while, the third most popular architecture was a little known thing called XAP, because it was in all of the 1-2 billion chips that CSR had made. XAP is a 16 bit processor in every way you can be a 16 bit processor: both the size of a byte (minimum addressable memory size) and the size of a word (size used for compilation) was 16 bit. You couldn't sub-address any larger types to serialise data. Also, the code space was separate from data space, and so function pointers were 24 bit (2 words). This meant that a lot of casting that developers take for granted wasn't possible (e.g. store a pointer in an int).

All of these choices meant that the XAP was very low gate count, and so very power and cost efficient for a surprisingly capable little processor.