diff --git a/Lombiq.HelpfulLibraries.AspNetCore/Extensions/HttpRequestExtensions.cs b/Lombiq.HelpfulLibraries.AspNetCore/Extensions/HttpRequestExtensions.cs
new file mode 100644
index 00000000..474eb2aa
--- /dev/null
+++ b/Lombiq.HelpfulLibraries.AspNetCore/Extensions/HttpRequestExtensions.cs
@@ -0,0 +1,65 @@
+using Lombiq.HelpfulLibraries.Common.Utilities;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Web;
+
+namespace Microsoft.AspNetCore.Http;
+
+public static class HttpRequestExtensions
+{
+    /// <summary>
+    /// Returns the query string without the leading <c>?</c> and without the keys in <paramref name="keysToExclude"/>.
+    /// </summary>
+    public static string GetQueryWithout(this HttpRequest request, params string[] keysToExclude)
+    {
+        var query = HttpUtility.ParseQueryString(request.QueryString.Value ?? string.Empty);
+        return string.Join('&', query
+            .AllKeys
+            .Where(key => key != null && !keysToExclude.Exists(key.EqualsOrdinalIgnoreCase))
+            .Select(key => $"{HttpUtility.UrlEncode(key)}={HttpUtility.UrlEncode(query[key] ?? string.Empty)}"));
+    }
+
+    /// <summary>
+    /// Returns the current URL but appends a new query string entry.
+    /// </summary>
+    public static string GetLinkWithAdditionalQuery(this HttpRequest request, string queryString, string key, object value)
+    {
+        queryString ??= string.Empty;
+        if (queryString.StartsWith('?')) queryString = queryString[1..];
+
+        var pageQuery = string.IsNullOrEmpty(queryString)
+            ? StringHelper.CreateInvariant($"{key}={value}")
+            : StringHelper.CreateInvariant($"&{key}={value}");
+        return $"{request.PathBase}{request.Path}?{queryString}{pageQuery}";
+    }
+
+    /// <summary>
+    /// Returns the current URL but appends a new query string entry.
+    /// </summary>
+    public static string GetLinkWithAdditionalQuery(this HttpRequest request, string key, object value) =>
+        request.GetLinkWithAdditionalQuery(request.QueryString.Value, key, value);
+
+    /// <summary>
+    /// Returns the current URL excluding any existing query string entry with the key <paramref name="key"/>, and with
+    /// a new <paramref name="key"/>-<paramref name="value"/> entry appended.
+    /// </summary>
+    public static string GetLinkWithDifferentQuery(this HttpRequest request, string key, object value) =>
+        request.GetLinkWithAdditionalQuery(request.GetQueryWithout(key), key, value);
+
+    /// <summary>
+    /// Returns the current URL but with the value of the query string entry of with the key <paramref name="key"/>
+    /// cycled to the next item in the <paramref name="values"/>. This can be useful for example to generate table
+    /// header links that cycle ascending-descending-unsorted sorting by that column.
+    /// </summary>
+    public static string GetLinkAndCycleQueryValue(this HttpRequest request, string key, params string[] values)
+    {
+        var query = HttpUtility.ParseQueryString(request.QueryString.Value ?? string.Empty);
+
+        var value = query[key] ?? string.Empty;
+        var index = ((IList<string>)values).IndexOf(value);
+        var newValue = values[(index + 1) % values.Length];
+
+        return request.GetLinkWithDifferentQuery(key, newValue);
+    }
+}
diff --git a/Lombiq.HelpfulLibraries.AspNetCore/Extensions/ServiceCollectionExtensions.cs b/Lombiq.HelpfulLibraries.AspNetCore/Extensions/ServiceCollectionExtensions.cs
new file mode 100644
index 00000000..dedf02d3
--- /dev/null
+++ b/Lombiq.HelpfulLibraries.AspNetCore/Extensions/ServiceCollectionExtensions.cs
@@ -0,0 +1,15 @@
+using Microsoft.AspNetCore.Mvc;
+using Microsoft.AspNetCore.Mvc.Filters;
+using Microsoft.Extensions.DependencyInjection;
+
+namespace Lombiq.HelpfulLibraries.AspNetCore.Extensions;
+
+public static class ServiceCollectionExtensions
+{
+    /// <summary>
+    /// Configures <see cref="MvcOptions"/> to add the <typeparamref name="TFilter"/> to the list of filters.
+    /// </summary>
+    public static void AddAsyncResultFilter<TFilter>(this IServiceCollection services)
+        where TFilter : IAsyncResultFilter =>
+        services.Configure<MvcOptions>(options => options.Filters.Add(typeof(TFilter)));
+}
diff --git a/Lombiq.HelpfulLibraries.OrchardCore/Contents/ContentHttpContextExtensions.cs b/Lombiq.HelpfulLibraries.OrchardCore/Contents/ContentHttpContextExtensions.cs
index 7a2588c4..f746a6b4 100644
--- a/Lombiq.HelpfulLibraries.OrchardCore/Contents/ContentHttpContextExtensions.cs
+++ b/Lombiq.HelpfulLibraries.OrchardCore/Contents/ContentHttpContextExtensions.cs
@@ -1,5 +1,6 @@
 using Lombiq.HelpfulLibraries.OrchardCore.Mvc;
 using Microsoft.AspNetCore.Mvc;
+using Microsoft.Extensions.DependencyInjection;
 using OrchardCore.ContentManagement;
 using System;
 using System.Collections.Generic;
@@ -76,4 +77,39 @@ public static string ActionTask<TController>(
         params (string Key, object Value)[] additionalArguments)
         where TController : ControllerBase =>
         httpContext.Action(taskActionExpression.StripResult(), additionalArguments);
+
+    /// <summary>
+    /// Returns the text of the MVC route value identified by <paramref name="name"/> (case-insensitive).
+    /// </summary>
+    public static string GetRouteValueString(this HttpContext httpContext, string name) =>
+        httpContext?.Request.RouteValues.GetMaybe(name)?.ToString();
+
+    /// <summary>
+    /// Returns a value indicating whether the current MVC route matches the provided <paramref name="area"/>, <paramref
+    /// name="controller"/> and  <paramref name="action"/>.
+    /// </summary>
+    public static bool IsAction(this HttpContext httpContext, string area, string controller, string action) =>
+        httpContext?.Request.RouteValues is { } routeValues &&
+        routeValues.GetMaybe(nameof(area))?.ToString() == area &&
+        routeValues.GetMaybe(nameof(controller))?.ToString() == controller &&
+        routeValues.GetMaybe(nameof(action))?.ToString() == action;
+
+    /// <summary>
+    /// Returns a value indicating whether the current page is a content item display action.
+    /// </summary>
+    public static bool IsContentDisplay(this HttpContext httpContext) =>
+        httpContext.IsAction("OrchardCore.Contents", "Item", "Display");
+
+    /// <summary>
+    /// Gets the content item from the database by the ID in the <c>contentItemId</c> or <c>id</c> route values.
+    /// </summary>
+    public static Task<ContentItem> GetContentItemAsync(this HttpContext httpContext, string jsonPath = null)
+    {
+        var id = httpContext.GetRouteValueString(nameof(ContentItem.ContentItemId));
+        if (string.IsNullOrWhiteSpace(id)) id = httpContext.GetRouteValueString("id");
+        if (string.IsNullOrWhiteSpace(id)) return Task.FromResult<ContentItem>(null);
+
+        var contentManager = httpContext.RequestServices.GetRequiredService<IContentManager>();
+        return contentManager.GetAsync(id, jsonPath);
+    }
 }
diff --git a/Lombiq.HelpfulLibraries.OrchardCore/Contents/TaxonomyHelper.cs b/Lombiq.HelpfulLibraries.OrchardCore/Contents/TaxonomyHelper.cs
index 62541fa8..1fa131f8 100644
--- a/Lombiq.HelpfulLibraries.OrchardCore/Contents/TaxonomyHelper.cs
+++ b/Lombiq.HelpfulLibraries.OrchardCore/Contents/TaxonomyHelper.cs
@@ -1,5 +1,8 @@
+using Newtonsoft.Json.Linq;
 using OrchardCore.ContentManagement;
 using OrchardCore.Taxonomies.Models;
+using System.Collections.Generic;
+using System.Linq;
 using System.Threading.Tasks;
 
 namespace Lombiq.HelpfulLibraries.OrchardCore.Contents;
@@ -20,4 +23,29 @@ await _contentHandleManager.GetContentItemIdAsync($"alias:{alias}") is { } conte
         await _contentManager.GetAsync(contentItemId) is { } contentItem
             ? contentItem.As<TaxonomyPart>()?.Terms?.Find(term => term.ContentItemId == termId)
             : null;
+
+    /// <summary>
+    /// Returns all child content items in a taxonomy tree.
+    /// </summary>
+    /// <param name="contentItem">The root of the tree to enumerate.</param>
+    /// <param name="includeSelf">
+    /// If <see langword="true"/> the <paramref name="contentItem"/> will be the first result so the collection is never
+    /// empty as long as  <paramref name="contentItem"/> isn't <see langword="null"/>.
+    /// </param>
+    /// <returns>An unsorted list of all child items.</returns>
+    public static IList<ContentItem> GetAllChildren(ContentItem contentItem, bool includeSelf = false)
+    {
+        var results = new List<ContentItem>();
+        if (contentItem == null) return results;
+        if (includeSelf) results.Add(contentItem);
+
+        var partTerms = contentItem.As<TaxonomyPart>()?.Terms ?? Enumerable.Empty<ContentItem>();
+        var itemTerms = (contentItem.Content.Terms as JArray)?.ToObject<List<ContentItem>>() ?? Enumerable.Empty<ContentItem>();
+        foreach (var child in partTerms.Concat(itemTerms))
+        {
+            results.AddRange(GetAllChildren(child, includeSelf: true));
+        }
+
+        return results;
+    }
 }
diff --git a/Lombiq.HelpfulLibraries.OrchardCore/Mvc/WidgetFilterBase.cs b/Lombiq.HelpfulLibraries.OrchardCore/Mvc/WidgetFilterBase.cs
index e55bcd27..0578eaa3 100644
--- a/Lombiq.HelpfulLibraries.OrchardCore/Mvc/WidgetFilterBase.cs
+++ b/Lombiq.HelpfulLibraries.OrchardCore/Mvc/WidgetFilterBase.cs
@@ -62,7 +62,11 @@ protected WidgetFilterBase(
     /// <summary>
     /// Returns the object used as the view-model and passed to the widget shape.
     /// </summary>
-    protected abstract Task<TViewModel> GetViewModelAsync();
+    protected virtual Task<TViewModel> GetViewModelAsync() =>
+        throw new NotSupportedException($"Please override either overloads of \"{nameof(GetViewModelAsync)}\"!");
+
+    protected virtual Task<TViewModel> GetViewModelAsync(ResultExecutingContext context) =>
+        GetViewModelAsync();
 
     public async Task OnResultExecutionAsync(ResultExecutingContext context, ResultExecutionDelegate next)
     {
@@ -83,13 +87,17 @@ public async Task OnResultExecutionAsync(ResultExecutingContext context, ResultE
         if ((AdminOnly && !isAdmin) ||
             (FrontEndOnly && isAdmin) ||
             (_requiredPermission != null && !await _authorizationService.AuthorizeAsync(user, _requiredPermission)) ||
-            await GetViewModelAsync() is not { } viewModel)
+            await GetViewModelAsync(context) is not { } viewModel)
         {
             await next();
             return;
         }
 
-        await _layoutAccessor.AddShapeToZoneAsync(ZoneName, await _shapeFactory.CreateAsync(ViewName, viewModel));
+        await _layoutAccessor.AddShapeToZoneAsync(
+            ZoneName,
+            ViewName == null && viewModel is IShape shape
+                ? shape
+                : await _shapeFactory.CreateAsync(ViewName, viewModel));
 
         await next();
     }