The Pimoroni scroll bit is a little display with a lot of pixels! Its 119 bright white LEDs are perfect for scrolling messages with your micro:bit, or for animations, graphs, and more!
Just slot in your micro:bit, then code scroll:bit with the block-based Microsoft MakeCode editor, or with MicroPython in the Mu code editor. It works in a very similar way to the built-in red LED matrix on your micro:bit, so if you've used that then you'll know exactly what to do.
You can code scroll:bit with the block-based Microsoft MakeCode editor, that'll get you started with the concepts of how to code a matrix of LEDs or, if you want to delve deeper, then you can use MicroPython in the Mu code editor.
To add the scroll:bit library in MakeCode, click on the cog at the top right hand corner, then "Add Package", then search for "scrollbit". You can find full instructions at the GitHub repository for the library.
Pimoroni's Getting Started with scroll:bit tutorial has a bunch of useful information and even embedded code examples (including how to make a spirit level) that are easy to download straight to your micro:bit. You'll be up-and-running in a jiffy!
Pimoroni's MicroPython library for scroll:bit is also available at GitHub, again with full instructions on how to get going with it.
Pimoroni have put together some lovely worksheets for scroll:bit, showing you how to get started, and build some simple projects with MakeCode blocks.