Stockfish (chess)

One of the most powerful chess engine as of 2023: computer chess competition.

CLI program implementing Universal Chess Interface: www.reddit.com/r/ComputerChess/comments/b6rdez/commandline_options_for_stockfish/

How to actually play against it: chess.stackexchange.com/questions/4353/how-to-install-stockfish-on-ubuntu So hard!