SF_13.2, SF_13.3, SF_14.0, SF_14.1, SF_14.2, SF_14.3 - https://www.progress.com/documentation/sitefinity-cms/autogenerated-field-types/

DemoComplexObjects.cs

using System.ComponentModel;
using Progress.Sitefinity.Renderer.Entities.Content;
using Progress.Sitefinity.Renderer.Designers.Attributes;

namespace SitefinityWebApp
{
    public class DemoComplexObjects
    {
      public ComplexObject Complex { get; set; }

      public MultiLevelComplexObject MultiLevelComplexObject { get; set; }

      public IList<string> List { get; set; }

      public IList<ComplexObject> ListComplexObject { get; set; }

      public IList<ComplexObjectNoDefaults> ListComplexObjectNoDefaults { get; set; }
    }
    
    public class ComplexObject
    {
      [DisplayName("String prop")]
      [DefaultValue("test")]
      public string ChildString { get; set; }

      [DisplayName("Int prop")]
      [DefaultValue(42)]
      public int ChildInt { get; set; }
    }

    public class ComplexObjectNoDefaults
    {
      [DisplayName("Boolean prop")]
      public bool BoolProp { get; set; }

      [DisplayName("Int prop")]
      public int ChildInt { get; set; }
      }

    public class MultiLevelComplexObject
    {
      [DisplayName("String prop")]
      [DefaultValue("testouter")]
      public string ChildString { get; set; }

      [DisplayName("Child complex prop")]
      public ComplexObject ChildComplexObject { get; set; }
    }   
}