Wow, I found an interesting FPGA Raspberry Pi Zero HAT on Digi-Key, Ice Zero with Lattice ICE (ICE40HX).
20191128/https://www.digikey.com/product-detail/en/trenz-electronic-gmbh/TE0876-02/1686-1162-ND/9816551
20191128/https://media.digikey.com/pdf/Data%20Sheets/Trenz%20Electronic%20PDFs/TE0876-02_Web.pdf
This gets me thinking, I’ve got to consider designing my Raspberry Pi Zero main board to also feature an “GPIO direct expansion slot” similar to the PDS expansion slot on the Macintosh SE, just for the sake of attaching these very interesting Raspberry Pi Zero HATs when I also have other stuff in a larger system to attach.