Quick answer — Mai Ootsuka worked on Non Non Biyori Nonstop (Character Design), Non Non Biyori Repeat (Character Design), Non Non Biyori Vacation (Character Design) and 32 more anime.
Mai Ootsuka worked on Non Non Biyori Nonstop (Character Design), Non Non Biyori Repeat (Character Design), Non Non Biyori Vacation (Character Design), Non Non Biyori Nonstop: Our Club Worked Hard (Character Design), Non Non Biyori (Character Design), The Demon Girl Next Door Season 2 (Character Design), Non Non Biyori: Repeat - Hotaru ga Tanoshinda (Character Design), Tanaka-kun is Always Listless (Prop Design) and 27 more.