As time goes on, I imagine more and more contrib modules will make use of Composer dependencies. As soon as your Drupal site needs just one contrib module with Composer dependencies, your entire site needs to be managed with Composer.

Responsive panels layouts for Panopoly and the Radix theme.
Radix Layouts is now part of Panopoly.
Responsive out of the box
Works with Panopoly, Panels IPE, and Panelizer
Easily extendable to support new layouts
Support for Responsive utility classes (You can easily hide and show panes based on mobile, tablet or desktop viewports)

Options Element is a module that provides a better mechanism to specify select list, checkbox, and radio button options. Rather than requiring the user to use strange syntax like "key|value" in a textarea, Options Element provides a clean interface for specifying options. Developers may use $element['#type'] = 'options' in their own modules. If JavaScript is disabled, any 'options_element' will degrade to the standard textarea for specifying options.

Options Element is a module that provides a better mechanism to specify select list, checkbox, and radio button options. Rather than requiring the user to use strange syntax like "key|value" in a textarea, Options Element provides a clean interface for specifying options. Developers may use $element['#type'] = 'options' in their own modules. If JavaScript is disabled, any 'options_element' will degrade to the standard textarea for specifying options.

The Architecture module provides reports documenting how your Drupal site is architected.

Currently it provides eight reports available as CSV downloads, plus three reports in the form of HTML pages.
CSV downloads

Content Types CSV
Entity Fields CSV - Information about entities, bundles, and fields
Nodequeues CSV
Image styles CSV
Menus CSV
Vocabularies CSV
Views CSV
User Roles CSV