Wiki fairies create beautiful content. They add pictures, color and style to the wiki. For example on this wiki Jonathan-Arkell along with Jorgen-Schäfer and others created wiki-css. Without that style sheet the wiki would look more like a boring WiLiKi page. wiki-fairies cousin is the wiki-gnome.
For more information see c2-on-wiki-fairies
Are you calling me A FAIRY?!? ;) (heh, thanks for the kudos.)