Photoshop: Color Wheel
There should be a color wheel option in the color panel. For example,some people like to be able to choose complimentary colors without guessing what is closest to opposite of the color they are using. It is visually easier. The Color Themes window is ridiculously giant, and the HUD color picker requires that someone has 2 hands (which, no, is not an issue for me, I just don't happen to be sitting on top of my keyboard while I draw, but looking into this made me realize how absurd it would be for someone with such limitations.) Also, right clicking a pen is just awkward, and some people might want to avoid it. Don't even try and tell me about Magic Picker or whatever other plug-in there is. You get money monthly from us, it is absolutely ludicrous that you don't have an option that doesn't cost extra money or open up our systems to viruses.