I found an interesting blog which has listed down list of SharePoint internal pages & their paths which can be accessed from below URLs. 

  • Add web parts to any page: append ?PageView=Shared&ToolPaneView=2
  • Add web parts to any page: append ?PageView=Shared&ToolPaneView=2
  • Create New Site Content: append Content /_layouts/create.aspx
  • Create New Site: _layouts/NewsbWeb.aspx
  • List Template Gallery: _catalogs/lt/Forms/AllItems.aspx
  • Master Page Gallery: _catalogs/masterpage/Forms/AllItems.aspx
  • Manage your Alerts _layouts/SubEdit.aspx
  • Create New Alert: _layouts/SubChoos.aspx
  • Manage Site Collection Administrators: /_layouts/mngsiteadmin.aspx
  • Manage Sites and Workspaces: /_layouts/mngsubwebs.aspx
  • Manage People: /_layouts/people.aspx
  • Manage User Permissions: /_layouts/user.aspx
  • Modify Navigation: /_layouts/AreaNavigationSettings.aspx
  • Modify Site Navigation: _layouts/SiteNavigationSettings.aspx
  • Recycle Bin: /_layouts/AdminRecycleBin.aspx
  • Site Directory: _layouts/SiteDirectorySettings.aspx
  • Save Site as Template: _layouts/savetmpl.aspx
  • Site Settings page: _layouts/settings.aspx
  • Create New Web Part Page: _layouts/spcf.aspx
  • Site Template Gallery : _catalogs/wt/Forms/Common.aspx
  • Site Column Gallery: /_layouts/mngfield.aspx
  • Site Content Types: /_layouts/mngctype.aspx
  • Site Content and Structure Manager: /_layouts/sitemanager.aspx
  • Site Usage Summary: /_layouts/SpUsageWeb.aspx
  • User Alerts: /_layouts/sitesubs.aspx
  • View All Site Content: /_layouts/viewlsts.aspx
  • Web Part Gallery: _catalogs/wp/Forms/AllItems.aspx
  • Web part maintenance mode: append ?contents=1 to the URL of the page
  • Open the page in Edit Mode: In Address bar, Type "javascript:MSOLayout_ToggleLayoutMode();" or "javascript:MSOTlPn_ShowToolPane(’2′);" in the Address bar
  • Add Web Parts Pane: ?ToolPaneView=2