What do you mean by standard sizes? FN 142s need approx a 24 x 36" liner to fit and then a cut out for top unless you're using solid bass pans. Most people who make liners on this site for sale will custom make the liners to the size you need.
I just made a whole bunch of them! Made 12 for about $60. I don't have quilting in mine though. I do have some with the quilt in the middle and I actually like them less. I made mine 34 x 23 and they fit well.