Indicate fan arts that use the same style as that of official materials intraseries.
Not to be confused with style parody, which indicate arts for one series that mimic official style of another series.
The equivalent tag on Pixiv is 野生の公式, although there are some more specific tags that specify which style. For example 野生のひまさん for Himaruya Hidekazu's style, 野生の天野 for Amano Akira's style, and 野生のカントク for Kantoku's style.