I looked at this question - Keyboard shortcut to switch focus between multiple displays on OS X 10.9+ - but the op doesn't seem to have the same goal as me.
I have a multi-monitor setup, and I have AltTab set up to only show windows on my current desktop and on my current monitor. This is how I want AltTab to work since I have a lot of windows open.
However, I also want a way to switch my focus to another monitor using a keyboard shortcut. For example, I want Ctrl + ⌘ + → to focus the top-most window on the monitor to the right without having to move my mouse.
Is there an app that can handle this? I'm aware of Keyboard Maestro, but am hoping to find a free option. If there is a way to do this with a custom script (python, js, or similar) I'm open to that as well.