I can't say I have an extensive list of Beat'em ups that I've played. But, from what I can recall (and maybe some don't qualify(?)) - it would be these...
Final Fight Shadow Force Golden Axe Teenage Mutant Ninja Turtles Dynasty Warriors Warrior Blade Ninja Gaiden (this one I actually hate, but I've played it so it goes in the list)
I'm not sure if Bad Dudes would qualify or not since it's a 2D side-scroller (no isometric plane).
So that's about all the beat'em ups I've played. I told ya it wasn't extensive enough.
If I were to add anything else it would have to be on a console or PC.
Well, technically, the TMNT I played on my cousin's SNES. But I'm sure that's arcade accurate.