Do courses without a certificate count in my extracurriculars ?
During quarentine I've been doing some courses that unfortunatly do not have certificates available, should I still credit them in my extracurriculars ?
I think it depends on what application format you are using. I think it's between 8 and 10 available slots depending on the Common or Coalition. If this new activity is more important to your profile than than some of the other current ECs on your application, I would submit it. If not, don't. Also, if they are a course of significance like AP Physics C, well then you perhaps even list it in your academic record under classes taken. If you received a passing or good grade submit that as well.
Well, you do need to give some proofs of your extracurriculars, and instead, I would like you to do something more creative like building something from your knowledge, starting a FB page or anything you want to and then you can include them in your application through essays or something.