Blitz Tactics

100% free chess tactics server, where you can solve chess puzzles at the speed of blitz chess. The puzzles on the site are from the Lichess tactics trainer and you can choose through different game modes.

ChessBites

Huge database of over 5 million games. Create your own personal databases. Search for games by ECO, players, position, endgame etc. Receive new games every week for your favourite openings.

Chess Puzzle Net

ChessPuzzle.net is an experiment in algorithmic discovery of chess puzzles. All positions are selected from real tournament games. The filter has also an option to select an opening variation.

Lichess

Lichess is a complete free chess platform with computer analysis for all your games. You can also import a game to analyze it or use the database of 2 million games of 2200+ fide elo players.

Chess Tempo

Free membership contains unlimited tactics per day with over 80.000 problems from real games, and create opening repertoires with up to 20.000 positions. Also, engine analysis of all rated games played.

The Chess Improver

One of the most comprehensive blogs with various articles from Nigel Davies and other writers. The articles will help you improve, covering openings, middlegames and endgames for all chess levels.

Douglas Griffin blog

Douglas Griffin is a chess author and translator and his remarkable blog is dedicated to chess history. There is a huge number of annotated games from various players, mostly translated from Russian.

Decode Chess

The only AI chess software that auto-explains the moves of a chess engine. The explanations reveal threats, attacking plans, tactical and strategic motifs. Free subscription provides 3 decodes per day.

SLCC YouTube

Saint Louis Chess Club is probably the No1 chess club in the world. In their YouTube channel there are almost 1000 lectures for various levels (kids / beginner / intermediate / advanced).  

Chessable

Chessable aims to make learning chess content as easy and efficient as possible. You can find a lot of free courses, using the filter at the left of the page. Also, search for the “Short & Sweet” series.