SewHouse7 and their Burnside Bibs. It's a simple and sophisticated take on the childhood classic, with a lot of easy variations.
If you're looking for something similar that is ready to wear, check out some of my picks at the end of this post.
I was a little intimidated at first, because it looked fairly complicated, but I was surprised at how easy it was (once I put together the pdf pattern pieces...)! The fabric, from Jo-ann's, was really easy to work with and the perfect fabric for casual and comfortable overalls. I was able to finish it pretty quickly and with minimal use of my seam ripper. I chose the more fitted version with the zipper, and while my zipper is not invisible like it was intended to be, my motto when it comes to zippers is "better done then perfect." Only minor adjustments for fit were necessary, and when I make them again, I think I will make the bib a little shorter. Overall, for my first PDF pattern, I was pretty pleased with the experience.
Pattern: Burnside Bibs by Sew House 7
Fabric: Sew Classic Bottomweight Rodeo Cotton from Joann Fabrics