Sandboxed Solution Gallery:
/_catalogs/solutions/Forms/AllItems.aspx
Workflow history hidden list:
/lists/Workflow History
Filter toolbar for Lists and libraries (Added by Asimaili):
?Filter=1
Site usage page (Added by @Dnyag):
/_layouts/usage.aspx
Site content and structure page (Added by @Dnyag):
/_layouts/sitemanger.aspx
Site settings page (Added by Aowworld):
/_layouts/settings.aspx
View all site content page (Site content) (Added by Aowworld):
/_layouts/viewlsts.aspx
Manage site collection features - CASE SENSITIVE - (Added by Vardhaman):
/_layouts/ManageFeatures.aspx?Scope=Site
Manage site features (Added by Vardhaman):
/_layouts/ManageFeatures.aspx
Get the version of the SharePoint server (Patch level) (Added by: John Liu):
/_vti_pvt/Service.cnf
Web Part Maintenance Page (Added by: Ricky):
?Contents=1
Show Page in Dialog View (Added by:Ricky):
?isdlg=1
Application page for registering SharePoint apps
/_layouts/15/appregnew.aspx
Save Site as a template
/_layouts/savetmpl.aspx
Sign in as a different user
/_layouts/closeConnection.aspx?loginasanotheruser=true
Enable SharePoint designer
/_layouts/SharePointDesignerSettings.aspx
Welcome Page (Default page settings)
/_layouts/AreaWelcomePage.aspx
Change Site Master Page
/_layouts/ChangeSiteMasterPage.aspx
Page Layouts and Site Templates
/_Layouts/AreaTemplateSettings.aspx
Master Pages library
/_catalogs/masterpage/Forms/AllItems.aspx
User Information List
_catalogs/users/simple.aspx
Quick Deploy List
Quick%20Deploy%20Items/AllItems.aspx
Open Page in Edit Mode
?ToolPaneView=2
Taxonomy Hidden List (MMS)
Lists/TaxonomyHiddenList/AllItems.aspx
User Information List:
_catalogs/users/simple.aspx
Force displaying the user profile in the site
collection:
collection:
/_layouts/userdisp.aspx?id={UserID}&Force=True
_layouts/ManageFeatures.aspx
SiteCollection Features:
_layouts/ManageFeatures.aspx?Scope=Site