You mean poker without real money? Because there are a lot of gambling sites, I would believe that some of them also offer poker. But please, there are better things to do with your money. You could donate it for example.
A friend of mine was an avid online poker player. He says the AI systems beat humans all the time, and that the platforms countered with AI AI detection systems which allow for a maximum tolerance of winning hands that is considered human level. As a response, players using AI systems added deliberate error rates to hide from the detection.
If they're worthless then, why play at all?
If they are scarce, convey any kind of status on the platform or unlock anything at all, then i assure you there will be someone gaming the system.
Poker requires gambling something with at least symbolic value, or else people don't care about winning or losing hands and just go all in recklessly all the time.
I recently started learning and playing poker, and I mostly play with fake money. Here's what I've used so far:
Pokerstars and GGPoker both have fake money options that you can play without depositing money. I used Pokerstars for a while as it was the only client I could get working on Linux (using bottles). They both have good mobile apps. I prefer GGPoker's interface so I've been using my Windows dual boot to play that when I want to on my computer.
Poker Brawl is a phone app where you can play correspondence heads-up poker with an ELO rating system. It's correspondence , so you only have to make a move once every three days. It's heads-up only, though.
I've found playing on real poker platforms with fake money to be best in terms of somewhat emulating real poker in terms of player behavior.
Feel free to comment with any questions and I'll try to help