It is a funny question, usually we do not wear sunglasses in overcast days but there are some exceptions. For example, there might be depressed people wearing it in overcast days trying to hide themselves. But if you like, you can also wear it. As there is not as much radiation as in sunny day, so the requirements for sunglasses wearing in overcast are not high. So you can choose any a type when you go out on overcast days.
If you choose sunglasses for wearing overcast day, you can choose yellow, orange, amber and brown tints for your sunglasses lenses. Yellow and orange lenses can increase contrast especially in a hazy, foggy and low light conditions. So, wearing yellow/orange sunglasses can provide your clear and better vision. Besides, amber and brown lenses can also be good choices because they can reduce block blue light and brighten vision on cloudy days. You can choose anyone of then that can flatter you. Hope this help you.