Why is there a lack of his artwork here?

Simple answer is that they merely haven't been uploaded yet. There's also a few images of his floating around under some of his other names.

Like Indrico said, SketchyAnon has changed his name three or four times in the past two years and a lot of his art has been uploaded under the name he had at the time and not under his current name. That and SketchyAnon doesn't have a Twitter or Pixiv account that he uploads under, which is where the majority of the images on this site are uploaded from. I uploaded a few of his pieces, but I'm not a big fan of his style and they appeared to not be very popular around here so I stopped.