Zenquarium is a happy iOS pet/aquarium game, with all game art made in Affinity Designer.
Affinity Designer is hands down the best graphic program I've ever used. I've dabbled with a lot of programs since I was young, but am mainly a programmer. Having a tool as thoughtfully designed as Affinity Designer turned what could have been a very painful process into one I absolutely loved.
(Our app store link if you're curious: https://itunes.apple.com/us/app/id1238993898)
Some plants and characters...
A screenshot of everything together. Icons also done in Designer!