The Powerpuff Girls
Craig McCracken's The Powerpuff Girls took a kindergarten-superhero premise and rendered it in clean UPA-inspired geometry, then undercut the sweetness with real wit and surprisingly hard action. The 1998 Cartoon Network series defined it, and the 2002 theatrical movie plus the holiday specials extended the same flat, graphic style into longer form.
The franchise reaches across television, film, games and a children's book, with a fighting-game cameo in MultiVersus keeping Blossom, Bubbles and Buttercup in rotation. The 2016 reboot is the clear weak link, trading the original's design discipline for something blander. Stick with McCracken's run and the early features and you get the version that mattered.
The The Powerpuff Girls franchise spans 2 series, 1 books, 3 films in the CrossBinge catalog.