For me projects with data ingestion and display from other sources are interesting, as you don’t have to think how to generate data yourself. There are a lot of cool ideas where you can download a lot of data for free. Some ideas I had for some time:

• IGDB - you can try to make a clone of their games list, or you can spin something of your own, like some graphs on most played games;
• OpenCelliD or OpenWeatherMap - if you’ve never played with maps technology like postgis, maplibre, you will find it very interesting displaying your own things on the map, you can even spice it up with something realtime via websockets;
• Membrane - this is an amazing technology, want to try it myself someday. You can try to clone a part of functionality of youtube videos, should be a very interesting experience!
• SprintInitializr - This is a great tool to generate an initial project for spring, and it would be an immense advancement in phoenix community if you could make something like this for phoenix and liveview, as currently a lot of people struggle with the default generator that is installed by hex, as there are still breaking changes in liveview. You could even mix it up with the generators provided by phoenix like gen.auth to offer truly a centralized experience for generating a initial project without any hassle.