My 2nd home brew computer was a Z80 based board. Very easy to use and the Z80 series stuck around for many years.
First home made computer was a Cosmac Elf back in '70s. Also had an old Intel 4004 based computer board. Worked but was slow and difficult to use. Included 4002 memories plus a handful of other really old stuff. Sold it to a computer museum in Germany. And - also had a collection of TRS-80 Model 1s based on the Z80. Bought first of these in 1979 and paid quite a bit for it. Yes... I am old.
Only popular 8-bit processor remaining now is the 65C02.