We have plenty of leather collars in widths of 1/2", 1", and 1 1/2" that are sturdy enough for near-24/7 wear.
Our heavier chain collars are well-suited for sleeping-in, as well.
We do not recommend sleeping in any collar with a bow, as this can bend, crease, or deform the bow.
We do not recommend sleeping in very delicate collars, as they can accidentally be snagged or pulled on while sleeping.