I) Take a look at short, 1-min videos for different widgets at Flutter Widget of the week by Flutter team.
II) You can also try a quickstart lab here on Flutter at Google codelabs.
III) Also refer to Flutter Documentation
I) We have made a short and precise medium blog here
I) Sensors and Camera
II) Dynamic UI
III) Rive animations
I) Optical Charachter Recognition(OCR)