On my keyboard the Opt-[ and Shift-Opt-[ keys print “ and ” respectively. Single quote uses ] as the base key. I’m not sure if Apple documents all of the Option key characters in a help file anywhere (probably not, since I bet each region/language keyboard is slightly different), but in the Keyboard system preference panel, there is an option to “Show Keyboard & Character Viewers in menu bar”. Turn that on, and you’ll get a floating keyboard display that highlights as you type. Hold down Option, and Option-Shift to see all of the possible characters that can be directly input without the special characters palette.