Before starting my character design I've scoured my memory and the Internet for existing characters in video games and animation that use their hair as hands/limbs or something else out of the ordinary in order to get an idea of different kinds of hair related powers and what my character should and shouldn't be able to do with her hair. ...Or more accurately, what my character's hair should be able to do to my character. She naturally won't get much choice in the matter, poor thing. But regardless, I think it'll be good practice to look at hair powers from both perspectives as I was originally thinking of my having my character star in a game where she used her hair based powers to get around due to lack of arms of her own... My idea may have developed into a narrative piece since then, but I still want to keep my options open in terms of character design so I can come up with something that really works and fits the tone of the story I'm trying to tell.
First we have Tiny Kong and Dixie Kong from the Donkey Kong video game series; two female monkey with long blonde hair who use their lengthy locks as weapons of mass destruction! ...Okay, so that's a slight exaggeration, but having played the games that they each appear in I can say that, while simple, their hair related powers work interestingly as means of transportation and combat. Both Tiny and Dixie have the ability to spin/hover through the air using their signature 'ponytail twirl' move, which allows them to clear large distances otherwise impossible to jump. Dixie can also use her ponytail to grab and throw enemies, while Tiny is capable of using her pigtails as weapons to whack enemies with once close enough. While the hair in these cases isn't particularly personified, its still a nice starting point.
Next we have Midna from The Legend of Zelda: Twilight Princess, who is a brilliant example of hair having a life of its own. While she's in clearly in control of her hair at all all times, her ponytail leaps into a grotesquely creepy hand that hover above her head in front of her, allowing her to grab, move, and throw things much larger than herself with relative ease. I really want my character's hair to have a distinctive hand shape with a narrower wrist so it's easily defined from the rest of the hair/arm like Midna's. I think this is important for the viewer to read the action clearly. I also really like how Midna's hair hand has long, pointed/jagged finger tips... In this case it's probably to make the hand more intimidating as it's being used as a weapon, since her hair normally has flat, rounded edges. But I'm thinking of having my character's hair have a more pointed ends so they hand easily mesh into fingers, so I think pointed fingers will work well for that.
Tangled, Disney's up-and-coming adaptation of the Rapunzel fairy tale, also decides to take a twist with the unusually long hair and similarly has Rapunzel able to control its actions at will to capture and tie up intruders. While this isn't really any different from the other examples other than in terms of sheer hair length, its nice to see a design where the hair isn't tied up somehow and yet is still perfectly functional. However this would detract from the conflict I want my character to have with her long hair as I need to her be annoyed and exasperated with how much it gets in the way, especially while wearing it down.
Video game heroine Bayonetta takes thinks to the extreme, her entire outfit consisting soley of her own hair wrapped magically around her body. Unfortunately this means that whenever she uses it as a weapon in battle, she becomes completely naked in the process... But regardless, having hair that can transform into a demonic dragon on a whim is certainly an interesting power and a great way to personify her hair as having an identity of its own. It's a little too much to be considered for my character, though...
Last but not least we have Niche, a young girl character from the anime Tegami Bachi or 'Letter Bee' in English. Likewise she uses her hair as weapons and extra limbs, but seems to have a far more diverse range of what she can do with it due to it's unnatural strength. Her hairy abilities range from simply picking things up/carrying them/throwing them around to climbing, aerial acrobatics, using her pigtails as swords, shields, and even skis and spider legs for moving around while her body is suspended in mid air. Her hair is also able to stretch/grow as much as the situation demands it, always snapping back to its original length when not in use, and she even uses it to gesture instead of or as well as her real arms for added exaggerated effect. All in all I really like how she's not limited to only one or two actions with her hair, making it feel like it's really alive and a creature in its own right, though I know a lot of what she can do it too fantasy orientated to apply to my character. Looking at these characters has made me realise I definitely want my character to have pigtails, though, as these seem to allow for the most interesting movements, and they'll have the added bonus of looking and acting like two extra arms rather than just one.