SP have alternate artwork on the back of the card rather than stats. When all are collected (currently 9) they make a new image. This is similar to Yugioh's Exodia or Pokemon's V-Union cards.

NTR depicts an image of sexual jealously or cuckoldry. This is also known as "netorare". 

FR in this set are largely comprised of characters from Touhou Project. FR's are printed semi-transparent which gives them a completely unique look! Watch the video to see exactly what these cards look like.