Android One phones like the Xiaomi Mi A1 and Moto X4 are great for a lot of reasons, and one of the main highlights is the stock Android experience they ship with. If you own a non-Android One phone and want to spruce it up a bit, you can now download the launcher that ships with these phones for free.
Amir Zaidi (also known as AmriZ) is the developer responsible for this, and by downloading the APK file he's created, you can get a fully working version of the Android One launcher on your phone right now. There's support for adaptive icons, you swipe up to access your app drawer, and there's even a working Google Feed on the left-most side.
If that sounds a lot like the Pixel 2 launcher, that's because it's incredibly similar. The two main differences are that the search bar is at the top rather than below the dock and there's no At a Glance widget, but depending on who you are, you might prefer that over the Pixel 2's UI.
In order to get the Android One launcher on your phone, just download the APK file to your phone, install it, and you'll be good to go. The launcher won't work if you own a phone with the Android One or Pixel Launcher already installed, but if you're reading this, chances are that's not the case.