I am a high school student from India. I participated in RMO (The first stage) and qualified for INMO. The questions asked in RMO were not very tough. Still, I could not solve most of the problems because I didn't know the theorems and axioms required to solve them. Although I have full command over my school syllabus, most of the topics for matg olympiads are not even taught at school. For example, Number theory. Some important theorems like Wilson's Theorem, Ptolemy's theorem etc. are beyond my school's syllabus.
Where can I get a comprehensive list of theorems (with proofs)? Can someone give me links to websites or names of books?