We propose a novel perspective on the design of toolbar buttons that aims to increase keyboard shortcut accessibility. IconHK implements this perspective by blending visual cues that convey keyboard shortcut information into toolbar buttons without denaturing the pictorial representation of their command. We introduce three design strategies to embed the hotkey, a visual encoding to convey the modifiers, and a magnification factor that determines the blending ratio between the pictogram of the button and the visual representation of the keyboard shortcut. Two studies examine the benefits of IconHK for end-users and provide insights from professional designers on the practicality of our approach for creating iconsets. Building on these insights, we develop a tool to assist designers in applying the IconHK design principle.