This module enables the use of a custom sort setting for children, using multiple properties.
Modules directory: https://processwire.com/modules/page-list-custom-sort/
Support forum: https://processwire.com/talk/topic/30410-pagelist-custom-sort/
This module is similar to ProcessPageListMultipleSorting by David Karich but is closer to what could (should?) be in the core as it adds the custom sort setting in both the template’s “Family” tab and in the page’s “Children” tab (when applicable).
Once a custom sort is set, it is applied in the page list but also when calling $page->children() or $page->siblings().
You can also apply the custom sort when calling $page->find("sort=_custom") or $pages->find("parent_id|has_parent=$id,sort=_custom"). Unfortunately this won’t work the same way sort=sort does if you only specify the template in your selector.