It’s called Krita. Maybe you’ve heard of it, but in case you haven’t, seriously, check it out! It’s really nice!
The best way I can describe this program is that it’s a combination of Easy Paint Tool SAI and Photoshop. And the best part is the program is completely free to download from their website. I think what I like most about it is that not only does it have a Stablizer like SAI does, but it has practically all the tools I ever use from Photoshop. Not saying it’s going to replace SAI or PS for me (at least not yet; I’m still learning my way around Krita lol), but it’s probably the only thing I’ve ever found that is coming close to doing it.
I put some screenshots under the cut!
IT DOES WORK ON MAC IM USING IT RIGHT NOW AND ITS ACTUALLY PRETTY NEAT I DONT USUALLY ADD ONTO POSTS LIKE THIS BUT I FELT THIS WAS IMPORTANT BC 999999% OF EVERYTHING FUCKS UP ON A MAC BUT THIS WORKS AND ITS FREE AND ITS SUPER NEAAAAATOOOO
.. as u can see im not even an artist. but. yknow. A+
I use this.