Extension components can be used in building projects, just like other components. The difference is that extension components can be distributed on the Web and loaded into App Inventor dynamically: they do not have to be built into the App Inventor system, and they can be imported into projects as needed. With extensions, the range of App Inventor apps can be virtually unlimited.
Download Links
1.
ShrinkEarn
2.
FC-LC
3.
Exe-io
4.
Clicksfly