On Pixiv as 本家 (Created by the Original Author). Works in this pool include the following:

• Art by official artists of their characters that is not featured in the character's game, anime or manga.
• Includes art by official artists of their characters wearing alternate costumes that are not official alternate costumes in the character's game, anime or manga
• Art by the official artists that depicts the scene not shown within the original serialized works
• Art depicting deleted scenes from an anime or manga by the anime or manga artist
• Art by official artists in their published personal artbooks (as opposed to franchise artbooks), including covers