I found a site which is very helpful in identifying watches: https://www.mastersintime.com/
It's most helpful if you know the brand of watch, for example Swatch or MK. I can use their function to find replacement straps which usually leads me to the watch I'm searching for. For Swatch for example, they list all the different product codes such as YS, YG etc. and show exactly how big the case is, whether different bands will fit the same watch etc.
Hope this helps you all identify more watches.