Unfortunately I can't come up with project ideas! Whilst learning, I'm always creating something, but it's usually a todo app, ecommerce concept, a portfolio or blog.
You should start working on random projects regardless of how they fit your portfolio, more for learning.
I would love to have few fresh ideas, even if some might never end up in the portfolio, or regardless whether I'll be able to finish them.
I am considering contributing to open source but the task feels overwhelming. (The best advice I heard on the topic is, to contribute on projects you already use, but what if that's not an option?)