I have a set of scripts that extend my screen to the right at max resolutions and reflows the workspaces in numeric order. It is generic enough to work with any number of displays.

You might need X11 python bindings and other dependencies that in general should be available on most distros.

See if it works for you, enjoy:

https://github.com/riccardomc/rcs/blob/master/scripts/.scrip...

If you are looking for usage from just i3, I am using xrandr to enable/disable multi-monitor:

    $mod+Shift+p exec "xrandr --output HDMI1 --auto --right-of eDP1"

(that with enable second screen through HDMI when Win+Shift+p is pressed)

    $mod+Shift+o exec "xrandr --output HDMI1 --off"

(that disables second screen)

    bindsym $mod+Shift+x move workspace to output HDMI1

(that moves an entire workspace to the 2nd screen or any screen with the given id)