Condless

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

liveseopro

Custom Image Attributes is a lightweight WordPress plugin which allows you to add custom attributes to images on your website. You can add attributes to single images or all images.
You can use this plugin to add attributes to images as required by some other plugins, such as for lightbox, analytics and seo purposes. Add any attribute you like. Examples include;
data-lightbox=image-ad1 
title=demo 
alt=demo 
fetchpriority=high 
click-id=promo1 
or id, style, class, data, toggle & more
Free Features 
Add attributes to all images on your WordPress website. 
Add attributes to single images 
Remove attributes 
Disable native lazy loading for an individual image
Get Support 
Get limited support for this free plugin via the support tab.

Custom Image Attributes

Add custom image attributes to any image. Great for adding attributes to images for lightboxes, SEO, analytics & more.

Default Attributes for WooCommerce vs Custom Image Attributes