-1. Is this not achievable with the character tagger? I just use the character tagger and I select multiple ocs and add the tags. Or I select one character with the tags I want and select the rest and just click the checkbox and hit the add button.
Would you use this feature? (read below first)
On my main account, I use the tagging system purely for sorting my characters to make it easier to find what I want. Example: haven't drawn are characters that I haven't gotten around to doodling yet, DRAW ME is the tag I link to others when doing art trades, and I have the adopted & designed by me tags to sort which ones I've made myself.
Currently, I add all the applicable tags by having a second tab open, and switching back and forth to type them all up.
Basically, I think it'd be good to have an optional drop-down menu to add tags that are already on one (or more) of your owned characters. It'd be a lot easier than typing everything out individually, and helps protect against any typos that might mess up your sorting system. Maybe a dropdown, or a button?