Check out Kathy Giori's Make magazine article Microcontrollers, Meet MicroBlocks:
MicroBlocks is a new programming language inspired by Scratch that runs right inside microcontroller boards such as the micro:bit, NodeMCU, AdaFruit Circuit Playground Express, and many Arduino boards.
The MicroBlocks system allows for dynamic, parallel and interactive programming, just like in Scratch, but with the twist of letting your projects run autonomously inside the board without being tethered to a computer. Thus, MicroBlocks provides the immediacy and liveness of tethered blocks programming, while supporting real-world applications that require precision timing, autonomous operation, or physically embedding the processor into projects. For example, one might write a program to record acceleration data, then embed the microcontroller and a small battery in a model rocket to explore G-forces at launch time.
In other words, MicroBlocks lets you program your boards exactly like you would in Snap4Arduino, S4A or the Arduino extension for Scratch, and when you are happy with your program you can just unplug the board from your computer and everything will keep running as if by magic!
With MicroBlocks, you can build your own "real world" digital instruments, interactive jewelry, electronic games and measuring devices, all by using blocks.
You can also run MicroBlocks in a Chrome or Edge browser without installing anything. To allow MicroBlocks to connect to your board, you'll need visit the "chrome://flags" page and enable the "Experimental Web Platform features" flag. See Running MicroBlocks in the Browser.
Visit the Learn section to find activity cards that will help you get started and then explore projects involving animation, colorful LEDs, sound, servo motors, communications, remote control, Internet of Things and more.