[enragedcacti]

I'm not a MacOS user so I don't know all that much about keyboard maestro's feature set, but with i3 all of it's keybindings are configured dynamically through the config file so you can map any keybind you want to invoke an arbitrary program. It won't come nice and prepackaged but you can do a whole lot just by using included tools and i3-msg, which lets you manage i3 windows programmatically.