I actually spent a fair amount of time looking for something like this, especially because it gets dark here so early in the winter. We actually made one, flexible LED strips glued and sewn to a regular collar with a tiny battery pack so we could turn it on and off, cost us about $15 to make.
They are for sale in many places, Google LED dog collar, or Illuminated K9 safety, there is a ton out there. Prices vary HUGELY. It varies from
small lit collar "tags" to higher tech working
police/SAR/Military dog supplies. Some get kind of crazy, blinking at variable intervals so the "enemy" will have a harder time targeting the dog (WHAT!!! makes sense, but wow!).
If you have an experience looking for one like mine, you'll search REALLY hard to find one, when you finally get one and they'll spring up in stores everywhere lol. Our pet store started carrying at least the lit tags about a month after we made our collar.