Is there a window switcher for GNOME that shows the actual window?
You can use the Coverflow Alt-Tab extension for GNOME shell. It's a
Replacement of Alt-Tab, iterates through windows in a cover-flow manner.
Refer to this for installing and managing GNOME extensions: How do I install and manage GNOME Shell extensions?
Another alternative would be using the Alt+Esc combination. It doesn't show any overlay or provide anything fancy, it just switches to the next window and so on.