Anything that interests you is usually a good idea. Do you have hobbies outside of tech? Do something with that. I like pokemon so for a educational project I'

Anything that interests you is usually a good idea. Do you have hobbies outside of tech? Do something with that. I like pokemon so for a educational project I'm making a pokedex with a mysql, golang, react stack. If you're into birdwatching make a bird encyclopedia/blog combo site. Maybe somewhere fellow birdpeople can share their bird stories, and experiences. If you can't think of any way to connect your hobbies into a project, then make a clone of a site or app you use a lot. Twitter, Hacker News, Reddit, Linkedin etc. You could also make a resume/profile site.