Is it possible to set up favorite projections in ArcGIS Pro?

Answer

1. Move the projection (.prj) file to the following location:

   C:\Users\<user profile>\AppData\Local\ESRI\ArcGISPro\Favorites

   Note:
   The Favorites folder does not exist in the directory above until a projection is added.
   
   If the AppData folder is not visible:
   a. Navigate to the Control Panel > Folder Options > View > Advanced Settings.
   b. Check the Show hidden files, folders, and drives check box.
   

2. Once the .prj file is in the Favorites folder, the file is listed under Favorites in the Map Properties dialog box. To access the Map Properties dialog box:
   1. Right-click Map in the Contents pane, and select Properties.
      
      
       
   2. In the Map Properties dialog box, navigate to Coordinate System > Favorites.
      
      

      Note:
      Unlike ArcMap, in ArcGIS Pro the functionality of sub-folders within the Favorites folder is unavailable.