My grandmother was a prolific crocheter, knitter and sewer. She used to make crochet covered hangers by the dozen, colour-coordinated to our bedrooms. I never really appreciated them, and over the years have given a heap away, thinking they were old-fashioned and collected dust.
I decided to learn to crochet them myself. After scouring the internet for a pattern I came up with one that worked for me, I needed simple to begin with. I have to say I was pleasantly surprised at how quickly and easily they came together.
If you want to make your own, and you can crochet trebles [double-crochet in US terms] then you can make these!!
Just chain 20 to begin with, and then treble crochet in the 3rd chain from the end, all the way back to the beginning. Then turn, and treble crochet back again. When your rectangle is as long as your hanger, slip-stitch to join at one end and along the long side of the tube, fit the hanger inside [the hook part should be sticking out where you're joining with slip-stitches] and continue slip-stitching to complete the cover.
You could then embellish by crocheting a scalloped edge or flowers along the bottom, but I was time-pressured so I have left these plain.