I'll be updating the image dump in the first posts with any images posted in this thread, and with any images I come across. One need to be part of the SAO Social Group in order to view the larger sizes of the images in that post; I can remove that and allow non-members to view the contents if anyone so wishes.
I'd also like to point out that searching for images without having read the first 2 or 3 volumes of L/N is a big no-no, as it is very easy to come across images that contain spoilers. Unfortunately, that's the case for a lot of the better fan art, so I'll post those pieces (if other people don't beat me to it) as the anime progresses.