aa-globe

This plugin has no settings. 
Just activate the plugin and check if sold out items have moved to the bottom of the list.

Catalog Sorting by Stock Status – In Stock First, Sold Out Last

This plugin changes the sorting of a catalog (or product category) so that out-of-stock items are always at the end of the list

joharyjoox

Add collapse and expand feature for repeater field instances for better sorting.
This plugin requires both the <a href="https://wordpress.org/extend/plugins/advanced-custom-fields/" rel="ugc">Advanced Custom Fields</a> plugin (version 4.0+ only) AND <a href="http://www.advancedcustomfields.com/add-ons/repeater-field/" rel="nofollow ugc">Repeater Field</a> paid add-ons.
<h4>Localizations</h4>
<ul>
<li>English</li>
</ul>

ACF Repeater Collapser Admin

My own review

Add collapse and expand feature for repeater field instances for better sorting.

Catalog Sorting by Stock Status – In Stock First, Sold Out Last vs ACF Repeater Collapser Admin