EasyAddonSetting (2.14)
Easy Addon Setting lets you turn addons ON/OFF for each character from one in-game window. Open it with a key or /charaddons, pick a character on the left, and tick the addons on the right. You can search addons, hide libraries, and switch every listed addon ON or OFF with one click. You can also copy one characters settings to several other characters at once. Characters with identical settings are color-coded, so differences are easy to spot.

