Tag for speed drawing

I've seen certain amount of posts where artists are challenging themselves to draw a decent image in X minutes.
post #1838752 is one of the recent examples which seems to be drawn in 30 minutes. Should we perhaps make a tag for such images, or maybe it exists already?

They're generally called ワンドロ (Wandoro, One Hour Drawing).
However, the definition is somewhat ambiguous and misleading.

speed drawing would probably be a good way to tag it as a general idea