Flutter, Google's UI toolkit for building natively compiled applications, offers a wealth of widgets that make developing beautiful and functional apps a breeze. In the "Best Flutter Widgets EVER!" video by Fireship, several standout widgets are highlighted for their ability to streamline and enhance app development.

1. ListView
   ListView is essential for displaying a scrollable list of widgets. It simplifies the creation of lists and supports both static and dynamic content. Developers can easily handle large data sets with its lazy loading feature.

2. GridView
   For displaying items in a grid format, GridView is the go-to widget. It's perfect for creating photo galleries, product listings, or any content that benefits from a grid layout. The widget offers customization options for defining the number of columns and handling spacing between items.

3. Stack
   Stack allows for layering widgets on top of each other, enabling complex UIs like overlapping elements and custom positioning. This widget is particularly useful for creating custom designs where components need to overlay.

4. AnimatedContainer
   For adding animations to your UI with minimal effort, AnimatedContainer is a powerful tool. It automatically animates changes to its properties, such as size, color, and alignment, making it easy to enhance user experience with smooth transitions.

5. Hero
   The Hero widget enables seamless transitions between screens by animating a shared element from one screen to another. This creates a more cohesive and engaging user experience, particularly in apps with complex navigation.

6. CustomPaint
   CustomPaint provides the flexibility to draw custom shapes and designs directly onto the canvas. This widget is ideal for creating unique graphics, charts, and custom UI elements that go beyond standard widgets.

Conclusion
These Flutter widgets are just a glimpse of what's possible with Flutter's robust framework. By leveraging these tools, developers can create highly interactive, visually appealing, and performant mobile applications with ease.