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

ReflectionMedia

This plugin allows sorting of posts alphabetically, by Post Title (ascending or descending) or Post Date (ascending or descending), customizable for each category.

WP Post Sorting

This plugin allows sorting of posts alphabetically, customizable for each category.

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