If you have a felted sock (unfortunate mishap that sometimes happens when hand knit, or purchased, 100% wool socks go through the dryer) you can turn your misfortune to good luck by cutting the sock up to make a YoSd coat.

If you've lost a sock you can also try to felt it's solitary mate. It only takes ONE felted wool sock to make each YoSd sized coat!

Here's the diagram of how to cut up your sock.

Not shown on the diagram: the sleeve pieces are sewn into tapered tubes and then sewn by hand into the armholes. I also sewed, and then trimmed away, a wedge shaped piece over the armholes to provide a shoulder seam and a bit of shaping to the lower part of the hood. When I hemmed the hood I tapered it gradually to meet the centre front of the jacket at the point where I wanted the first fastener.

made the toggle buttons out of beads.

With some modification and a larger, mens' work sized sock, you can also make a coat for a slim MSD sized doll.

It can be done for a doll as large as a Minifee if you have a tall enough sock.
The length of the leg portion of the sock must equal the distance from the top of the doll's head to the desired hem of the back. The toe section must be long enough to allow for the length of the sleeves once the hood is cut.

It might work for dolls that are smaller than YoSd if you either used a smaller sock, or altered where you cut the sock.