Check out https://bitbucket.org/mfeemster/keysharp/ and https://github.com/phil294/AHK_X11, two attempts at reimplementing AHK on Linux. The former is v2 but not usable yet, the latter is by me, v1 "classic" and somewhat incomplete.
Keysharp / AHK_X11 on the other hand ship their own runtimes that will be / are compatible with the actual programming language AutoHotkey v2 / v1 and thus cannot be used in conjunction with other languages, apart from shell invocation. For a detailed feature comparison with AutoKey you will have to research this yourself, but there's at least one feature which is exclusive to AHK_X11 right now, and that is accessibility-related commands such as ControlClick or WinGetText.