Clicking IDE icons using keyboard

Hi, I was wondering if there was a way (perhaps a plugin) to click icons in toolbars and editor gutter using the keyboard, without defining a million shortcuts for every possible action. For example, I highlighted clickable icons on a screenshot:

I know there are shortcuts for individual actions, but (1) there are so many buttons it seems impossible to define reasonable shortcuts for every icon in every tool window, let alone remember them afterwards, and (2) for the editor gutter icons you need to have the cursor in the correct place, which is much slower than just using the mouse.

One idea I have is a shortcut that shows a single character hint next to every icon visible on the screen, so that you can press the shortcut + one character to click the icon. Does anything like this exist?