All games browser playable unless stated otherwise.
FairGame - a multiplayer incremental. Looks simple but isn't (unless you start late). New rounds start every few days, if you miss the beginning just hang about for a bit, or ask in chat for tactics/strategies.
PedroPascalsTrianglesofPrestige - a game written for the April Fool's game jam last year. Don't let the timer trick you, this game should be completable within 5-6 years.
Louigi Verona's Bliss - I quite like his games and his website has more listed.
Emoji Recycling Centre - also made for this year's April Fool's game jam. It's slow, meditative, thoughtful and one of the best games I've played in a very long time.
Fundamental - I spent ages on the first world trying to do everything in one go. Madness. Someone took me by the hand and gently slapped me around the head and now I'm cranking through it.
Anti-Idle:The Game - Flash standalone, downloadable from the dev's Google drive. This game is the reason I created a Kongregate account back in ... 2011, it appears! 14 years of playing it and still not bored (although I have specific things I do now, such as defeating the Legendary monster in FCG because I do l like a CCG)
Cividlization 3 is out as early access/testing. Get in early!