I would check 3 things:
(1) that the fabric selvage does not say "for personal use only"
(2) that the pattern does not say "for personal use only"
(3) that the design itself does not have the copyright symbol (check by any photos or the back of packaging)
It used to be mainly the novelty prints that were not supposed to be used in quilts we sell, but the other day I actually saw a stripe fabric I had in my stash that said "for personal use only". I couldn't believe it. How can someone claim a wiggly stripe as an original design?!!! Still, it's not worth the headache to me to have to worry about lawsuits.
For fabrics that don't come with a selvage, I do my best to act on the information I have. I check whatever selvages were attached. I use common sense that if it has a Disney or storybook character on the fabric, that's almost certainly copyrighted. I know inadvertently missing a fabric copyright somewhere is part of the risk of doing business so I make sure to carry proper insurance and I have a great attorney that can hopefully keep my tiny business from going under in the event that my best efforts weren't enough.
I definitely wouldn't bother to sell anything that has a copyright or patent labeled right on the packaging, quilt photo or pattern without first contacting the designer. International law gives designers an automatic copyright of our designs for our life + 70 years. That has nothing to do with whether or not a pattern exists. If I go out and sketch a quilt design of my imaginary puppy sitting under a double rainbow next to a pot of gold, that design is mine & I retain all rights to that design. No one else is allowed to turn it into a pattern, copy the design or most of the design (at any size) into their own quilt for personal or commercial use, or copy the design in another media like painting or printmaking without my express permission (usually I'd want some kind of money for that, but if I'm in a generous mood I might give it away for free). I can decide whether other people are only allowed to copy the design for personal use, for limited commercial use, for media other than quiltmaking, or for patterns (with or without the "for personal use only" logo). That automatic copyright allows designers to receive appropriate compensation for our design time.
Many smaller designers will grant you written permission to make a small number of quilts from their design provided you bought the pattern & plan to make the quilt yourself start to finish. I always write them if nothing is indicated on the pattern itself (it usually isn't, but I do know one designer who writes her permissions on her patterns). If it's a design of purely on traditional blocks with basic solids for fabrics, then you have nothing to worry about. There is no copyright given to people who simply cut fabrics.
Of course, all of this is just what I do. There are people out there on the internet that will insist I am wrong & perhaps I am ... it just seems like a huge risk to me to take without a guarantee I won't spend years tied up in a legal process I have neither the patience nor desire to battle, not to mention the time and money.
Either way, good luck & happy quilting!
