https://makecode.microbit.org/projects/ - A list of creative simple ideas made by others in the microbit community
https://www.bbc.co.uk/programmes/articles/27vnTM9fHfsdl1yTWKGDRfd/nine-amazing-micro-bit-projects-discover-what-you-can-do-with-the-bbc-micro-bit -Interesting ideas, check out the baseball scoring system
https://www.microsoft.com/en-us/research/project/farmbeats-iot-agriculture/ - Real world farming problem, maybe you can help build your own solution to read and analyse data visually
Pin Ball Machine
Music Player
Simple Stem Ideas
Build 2 Player Games - Pong