Willow is an iOS app for Pokémon GO that is now available for 0.99¢ in the App Store. To be honest, if you are a hardcore Pokémon trainer, this app probably won't do much for you. The app icon is fantastic and the UI for the app is great! The app will tell you what Pokémon are weak against and how many candies it takes to make it evolve. Willow will also tell you what the catch rate is and what the egg hatch rate is too. That's about it! Looks great, no issues, and it has a ton of potential, but a bit lackluster right now.