For tactics
•Woodpecker method. - Recommended for every intermediate-advanced player
Strategy and middlegames
•How to reassess your chess (4th edition recommended)
Theoretical endgames
•100 endgames you must know by jeus de la vida
•Jeremy silman's complete endgame course
"Silman's Complete Endgame Course" is brilliant. Good for any level player, thorough but not confusing. Must read for anyone looking to improve their (end)game.
agree