You can use just about any IR remote with the ATV.
There is a feature called "Remote Learning" in the settings, the ATV will learn any IR remote you have.
You can do basic controls, such as up, down, left, right, menu, and select, or you can do an extended remote learning which is a lot more buttons that are not used as much, such as RW, FW, skip, etc.
If using the buttons do not interfere with the operation of the TV, I like to use the TV's IR remote, that way you only need one remote.
But, just about any other remote would work, as long as it is IR. I even tried using my Roomba's remote, and it worked.
[doublepost=1557715291][/doublepost]Oh yeah, a downside to using IR remotes is that you will not have a Siri, or a Home/tvApp button.
Also, you have to point it at the ATV to work (line of sight).
Other than these two things, I prefer using an IR remote, mostly for the D-pad, as I hate the touch pad and endless thumb swiping.