Traversable Wormholes: An introductory note to concepts and recent work on traversable wormholes.
The Moving Puncture Breakthrough: A literature review on a breakthrough in 2012 when obstacles in simulating black hole collisions were finally overcome.
Phases of Bismuth: A report on some theoretical and computational studies of the electronic structure of high pressure phases of bismuth.
David Tong: A series of lecture courses in theoretical physics taught by Professor David Tong. You can find his extremely well-written lecture notes here and some good practice questions.
Mark Srednicki: A pre-publication version of his well-written book on QFT which you can download for free. It's organised in a very nice way.
KITP Talks: A wide range of recorded physics talks at KITP.
IAS Video Lectures: A good collection of video lectures recorded at IAS.
Dexter Chua: A large collection of delicate latexed notes taken by him during his years at University of Cambridge. It covers almost all the pure maths courses taught at Cambridge and a good selection of courses in statistics and theoretical physics.
Physiknotes: A link listing some good lectures and notes, mostly in high energy physics.