I was searching through logs and old forum posts about authors' name of some TMW artworks, and I can't find a precise one...
I think that everybody know the "Fizzy" hairstyle in game? Well then I find the original author on OpenGameArt, but I can't find the one which adapted the work to fit TMW's playerset, nor in which license he published his work.
It seems that the person who adapted this work to TMW's playerset is somebody from TAW, as Chicka-Maria find it on their repository and then asked to get it added in TMW.
It could be good to clarify this as TMW doesn't use Creative Commons licensed graphics and as this work has been reworked by a TAW developer (which btw used CC-BY-SA 3.0 for most of their work).
And also, it's always good to know who did the work that you/we use.

Reminder: This CC license requier a share-alike and attribution of the author.