I have recently customised Zorin core by installing ArcMenu from Gnome Shell extensions
and noticed it also changes the lock screen and shows open windows:
You can also change the theming of the menu by a selection of its own colour schemes:
A plethora of menu styles (layouts):
Traditional:
Modern:
Touch Menu Layouts:
Simple Menu Layouts:
Launcher Menu Layouts:
Alternative Menu Layouts:
Which is what I am currently using, 'Raven':
such a cool extension, i like that you can use it to create a launcher button at the top and essentially pull of the cosmic search thingy, by binding it to a hotkey, epic feature
That should not be affected by ArcMenu. But the Extension is a really good One. I use it, too.
Shows I am getting old. I don't even remember posting this! 
Any other cool gnome extensions? That you may know of
@DotWayton Gnome extension "Burn my windows"
I think the issue now is the change with Gnome Extension Manager isn't the same as the web version. Additionally extensions need to be continually updated by the authors of the extensions to match the current Gnome Shell version. Yet another reason I guess why I am now more of a Plasma fan. Gnome wants to control the horizontal and the vertical, "do not adjust your TV Set"! (Can't remember which TV program that was from!).
That depends what You think is a ''cool Extension''. What I like to find for Gnome Desktop (basic Stuff and more):
