Which Cookie Clicker did you play
The reason most "games like Cookie Clicker" lists are useless is that they answer a question nobody asked. Cookie Clicker is not one game. Orteil released it on 8 August 2013 as a joke you could finish laughing at in an afternoon, and the Legacy update in February 2016 bolted an ascension system onto it that turned it into something people have now been playing for a decade. The version you played depends entirely on when you stopped.
So work out which one you liked before you take a recommendation.
If you played for an hour, you liked the escalation. Grandmas, then a portal, then a time machine, then the antimatter condenser, with the tooltip text getting steadily more unhinged as the numbers stopped meaning anything. The clicking was never the point. The joke was the point.
If you played for fifty hours, you liked ascension. You reset a save you had spent a week on, got heavenly chips for it, and found the next run was faster in a way that felt like getting away with something. That is a different pleasure and it is the one the whole modern genre is built on.
If you played for five hundred hours, you liked the spreadsheet. You had the wiki open. You knew which upgrade order was optimal for a golden cookie chain and you were timing your ascensions against a target rather than ascending when you got bored. At that point the cookies are a skin over an optimisation problem.
If it was the joke
Go and play Candy Box 2, by David "aniwey" L., free in the browser under GPLv3. It starts as a candy counter and turns into something much stranger. It has more actual game underneath it than Cookie Clicker ever does, and it is the closest thing to that feeling of the screen misbehaving.
Universal Paperclips by Frank Lantz and Bennett Foddy is free in the browser and takes a few hours. Same escalation, no cookies, and it ends rather than looping. If the part you enjoyed was watching a small business become an absurd one, this is the sharpest version of that in the genre.
We wrote about both, and about A Dark Room, in games like A Dark Room, because they share a trick Cookie Clicker does not.
The other honest answer here is that Cookie Clicker's specific brand of humour is rare. NGU Idle by 4G is the most reliable place to find it, free on Steam and Windows only, but it wraps that humour around several hundred hours of grind, so it is a strange fit for someone who wanted an afternoon. Swarm Simulator is the cheaper version of the same joke: the sentences describing your swarm eating never change tone while the numbers acquire suffixes you have not seen before, and it runs in a browser tab on a phone.
If it was ascension
This is the largest group and the best served.
Antimatter Dimensions is the one to play. It takes what Cookie Clicker does once and does it perhaps a dozen times: you reset for a currency, then reset the reset for a better currency, then the game reveals that the thing you were resetting was itself a resource. Every layer changes what you are optimising rather than just multiplying it, which is the part Cookie Clicker never gets to. It is open source under MIT and we host a copy, so it loads here with nothing phoning home.
Trimps is the other one. It is a bleaker, denser take on the same idea, with a real combat layer and a map you push through until you die and reset. It is free in the browser and free on Steam. Be warned that its opening two hours are genuinely slow and it does not explain itself.
Progress Knight is the small version, and worth an evening. You live a life, die, and are reborn keeping a fraction of what you learned. That is heavenly chips with a story attached, and it is finishable in a way the other two are not.
Clicker Heroes deserves a mention because it is the game most lists put first. Playsaurus released it in 2014, it is free to play, and its Hero Souls system is a straight, clean ascension loop. It is also thin next to anything above and the late game leans on a cash shop. Play it if you want exactly Cookie Clicker's shape with different art. Skip it if you want more game. If you have already played it and hit the point where the multipliers stop meaning anything, that stall has its own guide.
If it was the spreadsheet
Kittens Game is the answer, and it is not close. It is a village management game made of plain text where you are constantly short of storage, constantly balancing happiness against population, and constantly recalculating whether a building pays back before your next reset. People keep saves running for years. It is free in the browser, with paid Steam and iOS versions. Its licence forbids anyone else hosting it, so we link out.
After that, Trimps again, which rewards spreadsheet play harder than it rewards patience, and Synergism by Platonic, free in the browser and open source, which is more or less Antimatter Dimensions for people who found Antimatter Dimensions insufficiently arithmetical.
Why we link out to Cookie Clicker
We host some of the games on this site ourselves, because their authors released them under licences that allow it. Cookie Clicker is not one of them. There is no licence file and no permission granted to redistribute it, so the only correct link is Orteil's own copy, which is free and always has been. There is also a paid Steam version published by Playsaurus, released 1 September 2021, which adds Steam achievements and a soundtrack to the same game.
Where to start
Antimatter Dimensions, if you have no strong feeling about which of the three readers you were. It is free, it is here, and it makes its case within twenty minutes.