2. Chess Calculation Workbook / Grandmaster Training Camp (GM Sam Shankland)
Be wary of third-party document-sharing websites claiming to offer free PGN downloads of copyrighted books or Chessable courses. These downloads frequently violate copyright laws and risk containing malware. Calculation: A Workbook for Tournament Players - Chessable Download Calculation Workbook for Tournament Players pgn
A super-intensive calculation workbook designed by Olympic gold medalist Sam Shankland. It covers deep calculation, candidate moves, and defensive resources. Download Calculation Workbook for Tournament Players pgn
Sites like PGN Mentor offer massive, free archives of specific players and classic tournaments. You can download these files and "mine" them for tactics to calculate. Download Calculation Workbook for Tournament Players pgn
Websites like Modern Chess often include standalone PGN downloads with the purchase of their calculation and endgame courses.