diff --git a/core/lib/Drupal/Component/Plugin/CategorizingPluginManagerInterface.php b/core/lib/Drupal/Component/Plugin/CategorizingPluginManagerInterface.php
new file mode 100644
index 0000000..67e0e8a
--- /dev/null
+++ b/core/lib/Drupal/Component/Plugin/CategorizingPluginManagerInterface.php
@@ -0,0 +1,40 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\Component\Plugin\CategorizingPluginManagerInterface.
+ */
+
+namespace Drupal\Component\Plugin;
+
+/**
+ * Defines an interface for plugin managers that categorize plugin definitions.
+ */
+interface CategorizingPluginManagerInterface extends PluginManagerInterface {
+
+  /**
+   * Gets the names of all categories.
+   *
+   * @return array
+   *   An array of translated categories, sorted alphabetically.
+   */
+  public function getCategories();
+
+  /**
+   * Gets the sorted definitions.
+   *
+   * @return array
+   *   An array of plugin definitions, sorted by category and label.
+   */
+  public function getSortedDefinitions();
+
+  /**
+   * Gets definitions grouped by category.
+   *
+   * @return array
+   *   A nested array containing plugin definitions, keyed by category and
+   *   plugin id.
+   */
+  public function getGroupedDefinitions();
+
+}
diff --git a/core/lib/Drupal/Core/Plugin/CategorizingPluginManagerTrait.php b/core/lib/Drupal/Core/Plugin/CategorizingPluginManagerTrait.php
new file mode 100644
index 0000000..26fc17d
--- /dev/null
+++ b/core/lib/Drupal/Core/Plugin/CategorizingPluginManagerTrait.php
@@ -0,0 +1,109 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\Core\Plugin\CategorizingPluginManagerTrait.
+ */
+
+namespace Drupal\Core\Plugin;
+use Drupal\Core\StringTranslation\StringTranslationTrait;
+
+/**
+ * Provides a trait for the CategorizingPluginManagerInterface.
+ *
+ * The trait provides methods for categorizing plugin definitions based on a
+ * 'category' key. The plugin manager should make sure
+ *
+ * @see \Drupal\Component\Plugin\CategorizingPluginManagerInterface
+ */
+class CategorizingPluginManagerTrait {
+
+  use StringTranslationTrait;
+
+  /**
+   * An array of all available modules and their data.
+   *
+   * @var array
+   */
+  protected $moduleData;
+
+  /**
+   * Processes a definition to ensure there is a category.
+   *
+   * If the definition lacks a category, it defaults to the providing module.
+   *
+   * @param array $definition
+   *   The plugin definition.
+   */
+  public function processDefinition(&$definition) {
+    // Ensure that every block has a category.
+    if (empty($definition['category'])) {
+      $definition['category'] = $this->getModuleName($definition['provider']);
+    }
+  }
+
+  /**
+   * Gets the name of the module.
+   *
+   * @param string $module
+   *   The machine name of a module.
+   *
+   * @return string
+   *   The human-readable module name if it exists, otherwise the
+   *   machine-readable module name.
+   */
+  protected function getModuleName($module) {
+    // Gather module data.
+    if (!isset($this->moduleData)) {
+      $this->moduleData = system_get_info('module');
+    }
+    // If the module exists, return its human-readable name.
+    if (isset($this->moduleData[$module])) {
+      return $this->t($this->moduleData[$module]['name']);
+    }
+    // Otherwise, return the machine name.
+    return $module;
+  }
+
+  /**
+   * See \Drupal\Component\Plugin\CategorizingPluginManagerInterface::getCategories().
+   */
+  public function getCategories() {
+    $categories = array_unique(array_values(array_map(function ($definition) {
+      return $definition['category'];
+    }, $this->getDefinitions())));
+    natcasesort($categories);
+    return $categories;
+  }
+
+  /**
+   * See \Drupal\Component\Plugin\CategorizingPluginManagerInterface::getSortedDefinitions().
+   *
+   * @param string $label_key
+   *   (optional) The key used for the label in plugin definitions. Defaults to
+   *   label.
+   */
+  public function getSortedDefinitions($label_key = 'label') {
+    // Sort the plugins first by category, then by label.
+    $definitions = $this->getDefinitions();
+    uasort($definitions, function ($a, $b) use ($label_key) {
+      if ($a['category'] != $b['category']) {
+        return strnatcasecmp($a['category'], $b['category']);
+      }
+      return strnatcasecmp($a[$label_key], $b[$label_key]);
+    });
+    return $definitions;
+  }
+
+  /**
+   * See \Drupal\Component\Plugin\CategorizingPluginManagerInterface::getGroupedDefinitions().
+   */
+  public function getGroupedDefinitions() {
+    $grouped_definitions = array();
+    foreach ($this->getDefinitions() as $id => $definition) {
+      $grouped_definitions[$definition['category']][$id][$definition];
+    }
+    return $grouped_definitions;
+  }
+
+}