FlatUIKit
A collection of awesome flat UI components for iOS
...It supplies drop-in controls—buttons, alerts, segmented controls, switches—and category helpers for colors and typography so interfaces look clean and consistent. The emphasis is on simple shapes, solid fills, and crisp edges rather than skeuomorphic textures, making it easy to theme entire apps with a few palette choices. Because it’s built as UIKit subclasses and categories, integration is straightforward: you can adopt pieces incrementally without rewriting existing screens. The components are tuned for sensible defaults while leaving room for customization through appearance proxies and property setters. ...