Condless

WooCommerce plugin that sets default attribute for variable products automatically if only 1 option is in-stock.
<a href="https://en.condless.com/default-attributes-for-woocommerce/" rel="nofollow ugc">Documentation</a> | <a href="https://en.condless.com/contact/" rel="nofollow ugc">Contact</a>
Variable product of T-shirt with color attribute (White/Blue/Black) and size attribute (S/M/XL): 
If only Black T-shirts are in-stock: default color (Black), default size (none). 
If only Small T-shirts are in-stock: default color (none), default size (Small). 
If only White and XL T-shirts are in-stock: default color (White), default size (XL).
<h4>How It Works</h4>
<ol>
<li>Before product variations is displayed to the customer, the plugin will check each attribute, and if there is only 1 in-stock option it will be set as the default.</li>
</ol>
<h4>Features</h4>
<ul>
<li>Stock: Set option as default when it’s the only 1 in-stock.</li>
<li>Per Attribute: Set specific option as default in all products with that attribute (from the Edit Attribute screen)</li>
<li>Top: Set as default the first option of each attribute.</li>
<li>Out of stock: Disable out of stock variations.</li>
<li>Add to Cart button: In archive pages display for variable products the attribute name instead of: “Select options”.</li>
<li>Select options: In single product pages remove the select options text if default attribute is set.</li>
</ul>

Default Attributes for WooCommerce

WooCommerce plugin that sets default attribute for variable products automatically if only 1 option is in-stock.

Freemius

WUPO Plugins

The plugin <a href="https://wupoplugins.com/group-attributes-woocommerce/" rel="nofollow ugc">WUPO Group Attributes</a> from <a href="https://wupoplugins.com/" rel="nofollow ugc">WUPO</a> gives you additional possibilities to display product attributes. Group attributes together to have them shown in separate sections. This will help your visitors to quickly grasp the details of your offerings.
Works perfectly with existing products and attributes, there is no need to edit or adapt your already created products. Simply add the attributes to groups and they will be shown as a part of it.
<h3>Features</h3>
<ul>
<li>Grouping of Attributes 
Put the product attributes into individual groups for better visual appearance</li>
<li>Table coloring 
Define colors for customizing the attribute tables with support for odd/even rows</li>
<li>Fast loading of attributes 
Defined attributes from a group are being added quickly when loaded in the product edit page</li>
<li>Works with existing products 
There is no need to edit or adapt the existing products. The attributes will be shown under each group once defined</li>
<li>Customize the sorting 
Define the sorting of the attributes within a group, as well as the sorting of the different attribute groups itself</li>
<li>(Pro) Various Layouts 
Choose between layout options for presenting the attribute groups or create your own template for complete freedom</li>
<li>(Pro) Group sets 
Assign attribute groups to a set for direct loading of all attributes when creating or editing a product</li>
<li>(Pro) More settings 
Define if groups are shown above or below single attributes, or define a separate title for single attributes. 
Control if the attribute for dimension and weight should be shown within the single attributes or in a separate section with a customizable title</li>
<li>(Pro) Shortcode 
Add the attribute groups wherever you like on the website with shortcodes. Supported parameters include the layout option and product ids</li>
<li>(Pro) Duplicate attributes 
Create a copy/clone of an attribute with all terms with just one click from the admin</li>
</ul>
<a href="https://wupoplugins.com/group-attributes-woocommerce/" rel="nofollow ugc">The Pro version can be purchased here</a>

WUPO Group Attributes for WooCommerce

Organize product attributes into groups. These will be shown in separate sections on your product pages. Increase readability for your product propert …

Default Attributes for WooCommerce vs WUPO Group Attributes for WooCommerce