GetWidget
Most popular and easy to use open source UI library
GetWidget is an open‑source Flutter UI toolkit offering over 1000 ready‑to‑use widgets for mobile and web apps. Maintained by IonicFirebaseApp, it's designed to accelerate UI development, reduce boilerplate, and improve app aesthetics. The library is MIT‑licensed, community‑driven, and features components ranging from buttons and alerts to carousels and loaders.