One annoying thing is that nobody makes new 68k CPUs anymore. The only real source appears to be scavenged chips from China.
If you want to limit your retrocomputer design to only parts that are still manufactured, like I do: The only cpu choices appear to be: Z80, 68c02 and 68c816
Reminds me I used the 68332 68k based MCU 25 years ago. I just checked, can still buy them from digikey. Some packages are listed as not for new designs. But a couple are listed as active.
Which is a shame. Just from high level descriptions of the 68k architecture, compared to my own (albeit very limited) experience with x86 assembly, the 68k seems a much more elegant and easier to program architecture.
At $100 for '020 and $300 for '040 I don't see many hobbyists rushing for those. You can get pretty damn nice FPGA for that sort of money, even if I understand it's not quite the same.
If you want to limit your retrocomputer design to only parts that are still manufactured, like I do: The only cpu choices appear to be: Z80, 68c02 and 68c816