From here, a neat trick to “unminimize” a Mac application’s window using only the keyboard:
A very quick keyboard method to un-minimize a specific window or un-minimize all of an app’s minimized windows is this:
Command ⌘+Tab ⇥ to the app with minimized windows, but don’t release the Command ⌘ key.
While still holding Command ⌘ down, tap Down ↓ twice, first tap enters App Exposé, second tap takes you to the minimized windows,
To un-minimize all windows, press Option ⌥+Return ↩
To un-minimize a specific window navigate to the window you want with the arrow keys, then press Return ↩