You could have trouble finding ADM & ADMX Template downloads when you need them.

Maybe it's the keywords/tags,  maybe it's the different product groups, thinking about them in different ways.

Anyway, here's a selected collection of the ones you could go looking for.

Important

As of 2015/2016,  recently released Security Updates or Cumulative Updates, for Windows and/or Internet Explorer, are shipping updated ADMX/ADML files e.g. inetres.admx/adml for IE. So, if you can't find the setting you're looking for in the downloads section, you might need to grab the latest CU for Windows or IE to get the freshest ADMX/ADML. This concept also seems to apply to Win10 upgrades (e.g. 1507 -> 1511 -> 1607)...

Windows

• Administrative Templates (.admx) for Windows 10 May 2019 Update (1903)
• Administrative Templates (.admx) for Windows 10 October 2018 Update (1809)
• Administrative Templates (.admx) for Windows 10 April 2018 Update (1803)
• Administrative Templates (.admx) for Windows 10 Fall Creators Update (1709)
• Administrative Templates (.admx) for Windows 10 Creators Update (1703)
• Administrative Templates (.admx) for Windows 10 1607 and Windows Server 2016
• Administrative Templates (.admx) for Windows 10 1507 and 1511
• Administrative Templates (.admx) for Windows 8.1 Update and Windows Server 2012 R2 Update
• Administrative Templates (.admx) for Windows 8.1 and Windows Server 2012 R2
• Administrative Templates (.admx) for Windows 8 and Windows Server 2012 
• Administrative Templates (ADMX) for Windows Server 2008 R2 and Windows 7 
• Administrative Templates (ADMX) for Windows Server 2008 
• Administrative Templates (.admx) for Windows Vista 
• Group Policy ADM Files: This page provides a complete set of current and previously shipped Administrative Template files (.adm files) included by default in Windows operating system and service pack releases, beginning with Windows 2000 up to XP/2003
• Administrative Templates for Windows PowerShell: This page provides the Group Policy Administrative template file for Windows PowerShell. 
• Windows Service Pack Blocker Tool Kit: A blocking tool is available for organizations that would like to temporarily prevent installation of Service Pack updates through Windows Update. 
• Toolkit to Temporarily Block Delivery of Windows Server 2003 Service Pack 2: While recognizing the security benefits of Windows Server 2003 Service Pack 2 (SP2), some organizations have requested the ability to temporarily disable the automatic delivery of this update through Automatic Updates (AU) and Windows Update (WU).
• Microsoft DirectAccess Connectivity Assistant: The Microsoft DirectAccess Connectivity Assistant (DCA) helps organizations reduce the cost of supporting DirectAccess users and significantly improve their connectivity experience. This Solution Accelerator is part of the Windows® Optimized Desktop Toolkit 2010 (WODT 2010).
• Microsoft Azure Hybrid Connection Manager Administrative Templates: This download includes Group Policy Administrative Template files for Microsoft Azure Hybrid Connection Manager.

MS Edge browser

• Edge for business, select channel/version/build, then click GET POLICY FILES: Edge for business, select channel/version/build, then click GET POLICY FILES

MS Internet Explorer

• Administrative Templates for Internet Explorer 11: This page provides the Group Policy Administrative Template files for Internet Explorer 11.
• Administrative Templates for Windows Internet Explorer 10: This page provides the Group Policy Administrative Template files for Windows Internet Explorer 10.

  ** Warning: IE10 deprecates/removes the IEM methods.

  Refer: AskIEBlog

• Administrative Templates for Windows Internet Explorer 9: This page provides the Group Policy Administrative Template files for Windows Internet Explorer 9
• Administrative Templates for Internet Explorer 7 for Windows: This page provides the Group Policy Administrative Template file for Internet Explorer 7 for Windows.

Blocker Toolkits for MS Internet Explorer

• Toolkit to Disable Automatic Delivery of Internet Explorer 11: The Internet Explorer 11 Blocker Toolkit enables users to disable automatic delivery of Internet Explorer 11 as an important class update via Automatic Updates (AU) feature of Windows Update (WU).
• Toolkit to Disable Automatic Delivery of Internet Explorer 10
• Toolkit to Disable Automatic Delivery of Internet Explorer 9
• Toolkit to Disable Automatic Delivery of Internet Explorer 8
• Toolkit to Disable Automatic Delivery of Internet Explorer 7

MS Office

• Office 2016 Administrative Template files (ADMX/ADML) and Office Customization Tool: This download includes Group Policy Administrative Template (ADMX/ADML) and Office Customization Tool (OPAX/OPAL) files for Microsoft Office 2016.
• Office 2013 Administrative Template files (ADMX/ADML) and Office Customization Tool: This download includes Group Policy Administrative Template (ADMX/ADML) and Office Customization Tool (OPAX/OPAL) files for Microsoft Office 2013.
• Office 2013 Help Files: Office Fluent User Interface Control Identifiers: This download details the ControlIDs needed for OFF2013, if you want to disable specific UI controls, buttons, menu items, via a registry policy.
• Office 2010 Administrative Template files (ADM, ADMX/ADML) and Office Customization Tool: This download includes Group Policy Administrative Template (ADM, ADMX/ADML) and Office Customization Tool (OPAX/OPAL) files for Microsoft Office 2010.
• Office 2010 (Beta) Administrative Template files (ADM, ADMX/ADML) and Office Customization Tool: This download includes updated Group Policy Administrative Template and Office Customization Tool OPA files; an updated Office Customization Tool; and ADMX and ADML versions of the Administrative Template files.
• Office 2010 Help Files: Office Fluent User Interface Control Identifiers: This download details the ControlIDs needed for OFF2010, if you want to disable specific UI controls, buttons, menu items, via a registry policy.
• Microsoft Lync 2010 Client Group Policy Documentation: This download package contains the Microsoft Lync 2010 administrative template file (Communicator.adm) and a spreadsheet that lists the Group Policy settings for the Lync 2010 client.
• 2007 Office system (SP2) Administrative Template files (ADM, ADMX, ADML) and Office Customization Tool: This download includes updated Group Policy Administrative Template and Office Customization Tool OPA files; an...Customization Tool; and ADMX and ADML versions of the Administrative Template files. This update assumes that you have updated...
• 2007 Office system Administrative Template files (ADM, ADMX, ADML) and Office Customization Tool version 2.0: This download includes updated Group Policy Administrative Template and Office Customization Tool OPA files; an updated Office Customization Tool; and ADMX and ADML versions of the Administrative Template files for Microsoft Windows Vista and Microsoft Windows Server 2008.
• 2007 Microsoft Office System Open XML Format converters Administrative Template (ADM) version 2.0: This download contains an administrative template which can be used to modify the default behavior of the Microsoft Office Word, Excel, and PowerPoint 2007 Open XML Format converters.
• Microsoft Office Communications Server 2007 R2 Client Group Policy Documentation: This download package contains the Communicator.adm file and a Group Policies Spreadsheet that lists the Group Policy settings for Office Communications Server 2007 R2 clients
• Office Communicator 2007: Communicator 2007 Policies Documentation: This download package contains the Communicator.adm file and a Group Policies Spreadsheet that lists the Group Policy settings for Office Communicator 2007.
• Office 2003 Service Pack 3 Administrative Template (ADM), OPAs, and Explain Text Update: The download includes updated Group Policy Administrative Template files, OPA files, and an updated Microsoft Excel workbook that lists the Administrative Template policy settings and OPA settings.
• Microsoft Project 2002: System Policy Editor and Templates: The Microsoft Project 2002: System Policy Editor and Templates download includes the Microsoft Project 2002 system policy template. You must install the System Policy Editor and the template on your computer before you can create a system policy file.
• System Policy Editor and Office 97 Policy Templates
• Microsoft Office Configuration Analyzer Tool 1.1 ADM Template: The Office Configuration Analyzer Tool 1.1 (OffCAT ) provides a quick and easy method to analyze several Microsoft Office programs for common configurations that may cause problems

MS OneDrive NGSC

• OneDrive NGSC Administrative settings - Deployment package

MS Applications

• Microsoft Desktop Optimization Pack Administrative Templates: ADMX templates for MDOP products - UE-V and App-V

  These MDOP Group Policy Templates delivers .admx and .adml templates to manage policy across the enterprise for the following MDOP technologies:

  • App-V 5.0
  • App-V 5.0 SP1
  • App-V 5.0 SP2
  • MBAM 1.0
  • MBAM 1.0 R1
  • MBAM 2.0
  • MBAM 2.0 SP1
  • MBAM 2.5
  • UE-V 1.0
  • UE-V 1.0 SP1
  • UE-V 2.0
• Help for Windows Administrative Templates (ADMX): This page provides the Group Policy Administrative Template files for Help for Windows (WinHlp32.exe).
• Microsoft Application Virtualization Administrative Template (ADM Template): The Microsoft Application Virtualization ADM template allows you to administer App-V client settings via Preferences.

  The ADM Template for App-V 4.5/4.6 provides central client settings administration for App-V 4.5/4.6 deployment, including the following:

  • Client permissions
  • Client interface behavior
  • Client communication settings
• Windows Live Toolbar Administrative Template (.adm) File: Windows Live Toolbar administrative template file for Group Policy Object Editor
• Windows Search 4.0 for Windows XP (KB940157): Windows Search 4.0 is an updated component of Windows that enables instant search on your computer.
• Windows Search 4.0 for Windows XP x64 Edition (KB940157)
• Windows Search 4.0 for Windows Server 2003 (KB940157)
• Windows Search 4.0 for Windows Server 2003 x64 Edition (KB940157)
• Windows Desktop Search 3.01 for Windows Server 2003 (KB917013)
• Windows Desktop Search 3.01 for Windows Server 2003 x64 Edition (KB917013)
• Windows Desktop Search 3.01 for Windows XP (KB917013)
• Windows Desktop Search 3.01 for Windows XP x64 Edition (KB917013)
• Silverlight: Technical Resources Reference, includes code for creating custom administrative template.
• Windows Defender: Description of the Windows Defender Group Policy administrative template settings

MS Manageability

• Microsoft System Center Mobile Device Manager 2008 SP1 Resource Kit Tools - Server Tools: System Center Mobile Device Manager (MDM) 2008 Service Pack 1 (SP1) Server Tools provides tools to help administrators manage deployment and cleanup tasks in an MDM system
• Microsoft System Center Mobile Device Manager 2008 Resource Kit - Server Tools: System Center Mobile Device Manager (MDM) 2008 Server Tools provides tools to help administrators manage deployment and cleanup tasks in an MDM system.
• Microsoft® Forefront™ Identity Manager 2010 Group Policy Templates: This download contains the Forefront Identity Manager 2010 Group Policy templates.
• SCOnline Group Policy Administrative Template: Group Policy administrative template for Asset Intelligence Service

Administrative Template guides, samples, references

• Group Policy Documentation Survival Guide: This document provides links to documentation and other technical information for Group Policy in Windows Server 2008.
• Group Policy Search tool: You can use the Group Policy Search tool to search and find Group Policy settings.
• Group Policy Settings Reference for Windows and Windows Server: These workbooks / spreadsheets list the policy settings for computer and user configurations included in the Administrative template files delivered with the Windows operating systems specified. You can configure these policy settings when you edit Group Policy objects (GPOs).
  • WindowsServer2003SP2GroupPolicySettings.xls (includes Windows XP & IE6)
  • WindowsServer2008andWindowsVistaSP1GroupPolicySettings.xlsx (includes IE7)
  • WindowsServer2008R2andWindows7GroupPolicySettings.xlsx (includes IE8)
  • WindowsServer2012andWindows8GroupPolicySettings.xlsx (includes IE10)
  • WindowsServer2012R2andWindows8.1GroupPolicySettings.xlsx (includes IE11)
  • WindowsVistaGroupPolicySettings.xls (includes IE7)
  • Windows 10 ADMX spreadsheet.xlsx (includes IE11 and Edge)
• Group Policy Settings Reference for Windows Internet Explorer 8: This spreadsheet lists the policy settings for computer and user configurations included in the administrative template files (admx/adml) delivered with Windows Internet Explorer 8.
• Group Policy Settings Reference Windows Internet Explorer 9: This spreadsheet lists the policy settings for computer and user configurations included in the administrative template files (admx/adml) delivered with Windows Internet Explorer 9.
• Using Administrative Template Files with Registry-Based Group Policy: Explains the concepts, architecture, and implementation details for registry-based Group Policy, shows how to create custom Administrative Template (.adm) files, and includes a complete reference for the .adm language.
• Group Policy ADMX Syntax Reference Guide: This reference document describes the new Group Policy ADMX format. The intent of this document is to teach you how to create .admx and .adml files for custom Group Policy administrative template settings.
• Group Policy ADMX Schema files: This page provides the Group Policy Administrative Template ADMX schema files.
• Group Policy Sample ADMX Files: This page provides Group Policy Sample ADMX files.
• ADMX Migrator: ADMX Migrator is a snap-in for the Microsoft Management Console (MMC) that simplifies the process of converting your existing Group Policy ADM Templates to the new ADMX format and provides a graphical user interface for creating and editing Administrative templates.
• Starter Group Policy Objects (GPOs): Starter Group Policy objects (GPOs), introduced in Group Policy for Windows Server 2008, are collections of configured Administrative template (.admx) policy settings that you can use to create a live GPO. Each of the two packages in this download contains four starter GPOs.
• Security Compliance Toolkit: includes various tools, baselines and custom templates

Important notes

• New Group Policies in Internet Explorer 10
• Appendix B: Replacements for Internet Explorer Maintenance
• New group policy settings for Internet Explorer 11
• Missing Internet Explorer Maintenance settings for Internet Explorer 11