An integrated threat protection solution designed to detect, investigate, and respond to cyber threats across Microsoft 365 services.
If using Word in a Microsoft 365 subscription only 1 Calendar template is shown by default.
For more, type calendar into the Search field to see more – assuming you have Connected Experiences enabled in Word> Preferences> Privacy - Manage Connected Experiences.
If you have something other than MS 365 the availability of templates is limited. Follow Jeronimo's suggestion to visit the Microsoft web site in your browser: MS Templates