dansart

A Stock Manager that is built for speed and super easy to use! 
Just select the quantity to add or remove, or the price to set, scan the product’s barcode, and you are good to go! 
This plugin is designed to be used with a barcode scanner on a desktop. On mobile, there is a mobile scan functionality available.
Required Plugins: WooCommerce 7.1.0 or higher
If you like the Plugin, please leave some Stars or spent me a coffee. Thanks!

Super Easy Stock Manager

Requires Plugins: woocommerce WC requires at least: 4.7.0 WC tested up to: 10.4.3 License: GPLv3 or later License URI: http://www.gnu.

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.

Super Easy Stock Manager vs Default Attributes for WooCommerce