Content Creation rules for Optimizely CMS. Support rules defining where certain content types should be created. So you don't end up with a lot of banners in "for this page" folders.

ContentCreationRule.cs

using EPiServer.PlugIn;
using EPiServer.Shell.ObjectEditing;
using System.ComponentModel.DataAnnotations;

    /// <summary>
    /// Rule that specifies where a certain type of content should be put on creation
    /// </summary>
    public class ContentCreationRule
    {
        [Display(Name = "Content Type", Order = 10)]
        [SelectOne(SelectionFactoryType = typeof(ContentTypeSelectionFactory))]
        public virtual string ContentTypeID { get; set; }

        [Display(Name = "Destination", Order = 20)]
        public virtual ContentReference ParentToMoveTo { get; set; }

    }

    [PropertyDefinitionTypePlugIn]
    public class ContentCreationRuleList : PropertyList<ContentCreationRule> { }

ContentPlacerInit.cs

    [ModuleDependency(typeof(InitializationModule))]
    public class ContentPlacerInit : IInitializableModule
    {
        public void Initialize(InitializationEngine context)
        {
            var cevents = ServiceLocator.Current.GetInstance<IContentEvents>();
            cevents.CreatingContent += Cevents_CreatingContent;
        }

        private void Cevents_CreatingContent(object sender, ContentEventArgs e)
        {
            var rules = ServiceLocator.Current.GetInstance<IContentLoader>().Get<StartPage>(ContentReference.StartPage).ContentCreationRules;
            var rule=rules.FirstOrDefault(r => r.ContentTypeID == e.Content.ContentTypeID.ToString());
            if (rule != null)
            {
                if (!e.Content.ParentLink.CompareToIgnoreWorkID(rule.ParentToMoveTo))
                {
                    e.Content.ParentLink = rule.ParentToMoveTo;
                } 
            }

        }

        public void Uninitialize(InitializationEngine context)
        {
        }
    }

ContentTypeSelectionFactory.cs

using EPiServer.Shell.ObjectEditing;

    public class ContentTypeSelectionFactory : ISelectionFactory
    {
        private readonly IContentTypeRepository _repo;
        public ContentTypeSelectionFactory(IContentTypeRepository repo)
        {
            _repo = repo;
        }
        
        public IEnumerable<ISelectItem> GetSelections(ExtendedMetadata metadata)
        {
            return _repo.List()
                .Select(r => new SelectItem() { Text = r.Name, Value = r.ID.ToString() });
        }
    }

StartPage.cs

//...

    [Display(GroupName = Globals.GroupNames.SiteSettings)]
    [EditorDescriptor(EditorDescriptorType = typeof(CollectionEditorDescriptor<ContentCreationRule>))]
    public virtual IList<ContentCreationRule> ContentCreationRules { get; set; }
    
//...