InternetIsBeautiful

I can wholeheartedly vouch for lichess.org. Not only because of their privacy policy but for what they offer in terms of chess. Besides the standard game you get an analysis engine that points out good moves, how likely a player is to win, let's you switch sides, etc.

But my favorite thing is actually the different chess variants you can play. There's one where you are facing a legion of pawns, another where captured pieces explode and take down adjacent pieces and another where you get to replace captured pieces on the board. But my go to is simply chess with randomized but symmetrical positions in the backline (pawns stay the same). This makes every game unique and challenging; you actually need to think about your best moves from turn 1 instead of memorizing openings which is perhaps my biggest gripe with default chess.

Give it a try, I say 😉.