Most emulators have just been built/developed with what people are used to, or what they like, which has become more similar over the years. Your questions confuses me a bit, but if you are actually looking for a good front-end for your standalone emulators, try emudeck: https://www.emudeck.com/

You're probably seeing either retroarch or launchbox (or its full screen mode, bigbox)

Retroarch is an emulation suite that supports many systems, it has generally superseded many of the original emulators the various cores are based on

Launchbox is a front end that is pretty well polished, and so very popular

They’re all independent. There are other front ends that will add shine to the emulators like Launchbox or Emulation Station (desktop edition) if you find a list or just plain box art boring. Both have big picture mode for full screen.

I don't use windows but I heard of retrobat. Maybe that would work?