So let me see if I understand. You want a button that user can press to add their page to the list? That cannot be done with any standard features. However, what you can do is ask staff to enable DynamicPageList. This feature enables you to generate lists of pages based on category. What you could have users do it just add their page to a category when they are done creating it. Then use DynamicPageList on the fanmade pets page to generate the list.