Below are some resources I have found useful in the course of school teaching, as detailed here.
My own resources, hosted on this site, may be used freely for non-commercial purposes as wanted. In cases where copyright forbids reproduction of useful materials, I give links to the original publisher.
Wide range of short problems suitable for independent working, or to provide a base for extension. I have used only the 'primary' section of excercises, but the site also has sections for students up to GCSE. Problems on basic calculus and complex numbers may be suitable for an AS/A level introduction (as yet untried by me).
A gold mine of maths and science teaching resources for all levels. Mostly presented as scanned books, so searching is not easy. Free registration is necessary to access the library.