Justin Tadlock

Ever had a widget get stuck in a particular sidebar or widget area? Are your widgets missing when you switch themes?
This plugin will remove all widgets, setting everything back to the factory settings.

Widgets Reset

Allows you to reset all of your widgets, wiping the slate completely clean.

Trevor Anderson

Split sidebars and widget areas into responsive columns.
Two simple widgets are provided, “Layout: New Column” and “Layout: New Column on New Row”.
Simply place these in your widget area where you’d like to create a new column (split) or new row of columns.
Gutter size and responsive collapse options are available in the Customizer -> Widget Columns panel.

Tuxedo Responsive Widget Columns

Just tested this plugin, and it works exactly as I hoped for. I can now have complex layouts in any widget areas. 
Of course it's best used for horizontal widget areas like footers, etc...



Works perfectly!

Split sidebars and widget areas into responsive columns.

Widgets Reset vs Tuxedo Responsive Widget Columns