Hm, what we (my boyfriend and myself) had been looking for along the lines of anime lately were stencils from Cowboy Bebop, Ninja Scroll and Hellsing. There are a few of the more popular animes under the tv section of the site so you could probably just expound on that.
And for video games maybe just see what you could find for some of the more classic games? Those are sure to be more popular. Such as Mario, Zelda, the Final Fantasy series and the like. I remember seeing a lovely Link stencil in this forum not too long ago actually. But yeah, Stencilry doesn't really have a game section at all just a few stencils under characters so adding some more to that area could help increase traffic on the site.