Science Spot: Science projects and printable worksheets that can be completed with or without Internet access https://sciencespot.net/Pages/classhome.html
Learn Concord (includes physics and chemistry): A collection of hundreds of free K-12 STEM resources, from standalone models and simulations to short activities and week long sequences of curriculum materials. https://learn.concord.org/
SEPUPL HS: Science simulations, scientist profiles, and other digital resources for middle school science and high school biology
IB Chemistry (grades 11 & 12): Richard Thornley in chemistry has good videos that break down most topics in chemistry at the grade 11 and 12(cegep) level. It follows the IB platform.
Andrew Weng also has a set of playlists geared towards the grade 11 and 12 IB program. He also has a website that has old exams and explanations.
Innerbody: With interactive models and detailed explanations, this website will help them learn more about the internal mechanics of the human body.
Positive Physics: An online physics problem and video bank designed for conceptual, standard, honors or AP1 physics. https://www.positivephysics.org/home
Think IB: This is also geared towards IB. It has a lot of practice and multiple choice questions.
Chem Matters: High school chemistry topics