Chess Tempo Database - Chess Tempo Database gives you a library of more than 2 million searchable chess games.
Lichess - The complete chess experience, play and compete in tournaments with friends others around the world.
DecodeChess - AI chess tutor and analysis
XBoard - XBoard, also known as WinBoard on Microsoft operating systems, is a free graphical user interface...
ChessPad - ChessPad is a feature-rich chess game viewer and PGN file editor available for Windows.
Chess.com - Play chess on Chess.