I have found 4 or so different uninsulated hunting bibs, but they all have cons. They are all basically camo work overalls (no boot zip, no full front zip, 60/40 cotton/poly). For medium insulation, I would go to MidwayUSA and look at their store brand (such as Prairie Creek).
I have looked for all polyester, unlined bibs with all the pockets and zippers as insulated bibs, and I don't think they exist. Carhartt might be better but they are 100% cotton and their uninsulated versions are all solid colors.
Be prepared for warm weather hunting with this lightweight uninsulated camo bib. This comfortable camo overall will blend in with any terrain.
naturalgear.com
RedHead® Silent-Hide® Uninsulated Bibs for Men bring the perfect outer layer for any hunt. Whether you need to stay cool on a warm day or add a functional camo layer to inner insulating layers, you're
www.cabelas.com
I have the redheads above and the quality is good.
Mossy Oak's solution to the need of simple, lightweight hunting bibs. Camo overalls have long been a staple in the hunting world.
store.mossyoak.com
Mossy Oak probably has several if you look.
Round House Realtree AP Made in USA camo overalls are specifically for hunters. These American made comfortable rugged and versatile overalls are a hunter's dream.
www.round-house.com
The Round House ones seem like they'd probably be the best made, but they lack cargo pockets (which I need for the walk in and out).
MEDIUM insulation.
I have these (midwayusa stuff goes on massive sale in the summer and I think it is the best bang for your buck in hunting clothing).
The ultimate workhorse, the MidwayUSA Prairie Creek Softshell Bibs will soon become your favorite hunting apparel. Constructed from a durable polyester...
www.midwayusa.com
and they are excellent except they lack a double front zipper (true of all Midwayusa brand bibs). But I found a way to install a double zipper on my own for less than 20 bucks. Which is get one of these
Replace your broken and flimsy zipper pulls with FixnZip® zipper sliders. They’re designed to provide lasting durability no matter what you need to fix.
www.fixnzip.com
off Amazon for half what the official site asks for it.