For developing a custom logic module I used GrrenPAK5 logic chips. They are absolutely tiny! (2x3mm with 20 pins).
So for this project I built a PCB with DIP-20 outline to solder on the tiny chips and plug them in a breadboard/proto-board/flying-wires. Silego, the company building the GreenPAK5 chips now has something similar in their store. So well. This is now obsolete before it even started properly.