These Pokemon are the work of designer and illustrator Daniel Mackey. If your first thought is that they look like something Finn would take a swing at, you're not alone, that's exactly what I was thinking as well.
I like how they take a series that's primarily about cute animals, drawn from a Japanese perspective, and does kinda the same thing but in a contemporary Western style. While making them look even goofier in the progress.
You can see of the Pokemon at Daniel's site, and buy some prints at his store.