I've used the Motorola 6800, 6809 68HC11 and 68000 series.
6800 is 8 bit data, 16 bit address (so 0-65535 range).
6809 is 8 or 16 bit data, 16 bit address, as above; the external data bus is still 8 bit, so 16 bit transfers take two memory cycles.
However, it supports relocatable code so with a suitable memory management unit a 6809 system can have eg. a megabyte of RAM.
The HC11 is something of a cross between a 6800 and 6809, 8 bit data bus and 16 bit address, with some internal peripherals and memory, for use in single-chip or minimal component systems & embedded controllers.
The 68000 series support 8/16/32 bit data sizes, with a 32 bit internal data bus and either a 20, 24 or 32 bit address bus.
The address is 32 bit in the CPU, but not all address lines are available as pins, in some package versions.
Likewise, the external data bus could be 8, 16, or 32 bit - so the CPU would do multiple memory cycles if needed to read or write a full word.
If I remember right, the very first release version was the 68008, with 8 bit external data bus and 20 bit external address bus: