iOSStash - A huge collection of app-related tools
Thunkable - Powerful but easy to use, drag-and-drop mobile app builder.
Lightwell - App creation platform for creatives.
BuildFire - BuildFire is the easiest way for small businesses to build a mobile app in a matter of minutes for iOS and Android.
iOS Cookies - A hand curated collection of iOS libraries written in Swift
MIT App Inventor - App Inventor is a cloud-based tool, which means you can create apps for phones or tablets right in your web browser.