
Quick answer — Hiroki Takagi worked on GTO: Great Teacher Onizuka (Design Works), Detective School Q (Prop Design), Ghost Stories (Design Works) and 2 more anime.
Hiroki Takagi worked on GTO: Great Teacher Onizuka (Design Works), Detective School Q (Prop Design), Ghost Stories (Design Works), The World is Still Beautiful (Episode Director), Dominion Tank Police (Character Design).