Is there a feature like Alt + Tab for groups?

Solution 1:

I understand what you are asking but I don't know of any way to do exactly what you are asking, however with Unity you can press Super + [NUMBER] to show the most recently open applications in a group and then the same combination again to show all of the open windows of that app, using the scale plugin.

e.g. Chromium is the second app down in my launcher and if I were to be currently in a different app but wanted to switch to Chromium I would press Super + 2 and I would be there, I could then press it again and it would show all of my windows.

Solution 2:

As of 16.04 this feature is implemented.

If AltTab is pressed it shows application groups

Once you pause over a group, or press ` while holding Alt it expands to window switcher