The nice thing about open source is that you're going about it all wrong.

You're not looking for a project "actively looking for new contributors". You're looking for a project you want to contribute to. You don't ask/interview for a spot on the team; you come up with a feature you will use, write it, and send diffs.

Even a project like Wordpress, which has a small army of PHP contributors, is "open to contributions". If you write something genuinely useful, send diffs, and are willing to transfer your rights to the code, chances are they'll seriously consider it. Of course, Wordpress probably "wants" you to build a plugin, not a core modification. But if your best idea is a core modification, just go write it.

You're overthinking this. Consider whether that's a sign that you're procrastinating.