Other resources

Kevin Zhou’s handouts - the best resource for learning Olympiad physics. Many important resources can be found in the syllabus for the handouts. You may also want to look at his advice.

Stefan Ivanov’s resources - plenty of useful things here, including a more comprehensive archive, errata list and handouts.

PhODs resources - cool resources from the physics olympiad discord server

My notes - I do not recommend it for learning physics, but you may find some interesting things in here.

I have also modified some classic IPhO/APhO problems to showcase interesting things: IPhO 1992 T1 (Solution) and APhO 2005 T2B (Solution)