The amount of hand-drawn animation that went into Cuphead is a marvel.
There a bunch of really interesting examples just using Ubisoft's UbiArt framework such as Rayman Legends, Child of Light, and Valiant Hearts.
Speaking of Ubisoft and open source, Ubisoft originally announced UbiArt as an engine/framework intended to be open sourced. It's a shame that Ubisoft never followed up on that promise.
Supposedly it hasn't been used for a game since 2015 because it was "hard to use", but that seems more of a reason to open source it, perhaps to see if community interest could help where internal-only work struggled. A lot of open source starts hard to use and takes a village to make it better. (Blender, also mentioned here, might just be a poster child of that, too.)
