Here is the code to put at the top of your talk page to display a 'hidden' section that will show all of your user subpages;
== Index of my sub pages ==
{| class="wikitable collapsible collapsed"
! My subpages
|-
| <div class="infobox">Subpages for this user:((Special:Prefixindex/User:((BASEPAGENAME))/))((Special:Prefixindex/User talk:((BASEPAGENAME))/))</div>
|}
This is what it looks like;