Hello! I haven't been around for awhile, but I saw this today and thought I would share. Apparently a fabric company called Paintbrush Studio Fabrics is going to print fat quarters in yardage, calling it a Flat Fat Stack. I'm guessing it will work in multiples of two or four. It says they will be slightly larger than 18"x21", which I appreciate. I hope this becomes a thing:
https://pbsfabrics.com/pages/flat-fat-stack