Lichess is an online chess game and community. It is free and open source, ad-free and subscription-free. You can play against your friends, random strangers and the computer. You can create teams to compete in tournaments. There are tournaments going on all the time.
There are different game modes available, but I don’t really touch these. Chess960, King of the Hill, Three-check, From position. You can request that your game is analysed by a chess engine, it gives you suggestions on what you should have done. I like how it shows a graph of how much of an advantage one player has over one another.
Lichess is also good for becoming better at chess. Chess puzzles are available in the training section, where you have to choose the best move in a given situation, and follow it through to checkmate. Players can create their own puzzles.
It is truly better than the alternatives. Chess.com is cluttered with ads and has an uglier design - minimalism is the way forward. Lichess is free and open source, and always will be.