This is a non-production site

ObjectWithPluginCollectionInterface

class \Drupal\Core\Entity\EntityDisplayBase extends \Drupal\Core\Entity\Display\EntityDisplayInterface implements \Drupal\Core\Config\Entity\ConfigEntityBase
class \Drupal\Core\Entity\Entity\EntityFormDisplay extends \Drupal\Core\Entity\Display\EntityFormDisplayInterface implements \Drupal\Core\Entity\EntityDisplayBase
class \Drupal\Core\Entity\Entity\EntityViewDisplay extends \Drupal\Core\Entity\Display\EntityViewDisplayInterface implements \Drupal\Core\Entity\EntityDisplayBase
class \Drupal\Tests\Core\Config\Entity\EntityDisplayBaseMockableClass implements \Drupal\Core\Entity\EntityDisplayBase
class \Drupal\Tests\Core\Config\Entity\Fixtures\ConfigEntityBaseWithPluginCollections extends \Drupal\Core\Entity\EntityWithPluginCollectionInterface implements \Drupal\Core\Config\Entity\ConfigEntityBase
class \Drupal\Tests\Core\Config\Entity\TestConfigEntityWithPluginCollections implements \Drupal\Tests\Core\Config\Entity\Fixtures\ConfigEntityBaseWithPluginCollections
class \Drupal\Tests\search\Unit\TestSearchPage implements \Drupal\search\Entity\SearchPage
class \Drupal\block\Entity\Block extends \Drupal\block\BlockInterface, \Drupal\Core\Entity\EntityWithPluginCollectionInterface implements \Drupal\Core\Config\Entity\ConfigEntityBase
class \Drupal\field_layout\Entity\FieldLayoutEntityFormDisplay extends \Drupal\field_layout\Display\EntityDisplayWithLayoutInterface uses \Drupal\field_layout\Entity\FieldLayoutEntityDisplayTrait implements \Drupal\Core\Entity\Entity\EntityFormDisplay
class \Drupal\field_layout\Entity\FieldLayoutEntityViewDisplay extends \Drupal\field_layout\Display\EntityDisplayWithLayoutInterface uses \Drupal\field_layout\Entity\FieldLayoutEntityDisplayTrait implements \Drupal\Core\Entity\Entity\EntityViewDisplay
class \Drupal\filter\Entity\FilterFormat extends \Drupal\filter\FilterFormatInterface, \Drupal\Core\Entity\EntityWithPluginCollectionInterface implements \Drupal\Core\Config\Entity\ConfigEntityBase
class \Drupal\image\Entity\ImageStyle extends \Drupal\image\ImageStyleInterface, \Drupal\Core\Entity\EntityWithPluginCollectionInterface implements \Drupal\Core\Config\Entity\ConfigEntityBase
class \Drupal\layout_builder\Entity\LayoutBuilderEntityViewDisplay extends \Drupal\layout_builder\Entity\LayoutEntityDisplayInterface uses \Drupal\layout_builder\LayoutEntityHelperTrait, \Drupal\layout_builder\SectionListTrait implements \Drupal\Core\Entity\Entity\EntityViewDisplay
class \Drupal\media\Entity\MediaType extends \Drupal\media\MediaTypeInterface, \Drupal\Core\Entity\EntityWithPluginCollectionInterface implements \Drupal\Core\Config\Entity\ConfigEntityBundleBase
class \Drupal\rest\Entity\RestResourceConfig extends \Drupal\rest\RestResourceConfigInterface implements \Drupal\Core\Config\Entity\ConfigEntityBase
class \Drupal\search\Entity\SearchPage extends \Drupal\search\SearchPageInterface, \Drupal\Core\Entity\EntityWithPluginCollectionInterface implements \Drupal\Core\Config\Entity\ConfigEntityBase
class \Drupal\system\Entity\Action extends \Drupal\system\ActionConfigEntityInterface, \Drupal\Core\Entity\EntityWithPluginCollectionInterface implements \Drupal\Core\Config\Entity\ConfigEntityBase
class \Drupal\workflows\Entity\Workflow extends \Drupal\workflows\WorkflowInterface, \Drupal\Core\Entity\EntityWithPluginCollectionInterface implements \Drupal\Core\Config\Entity\ConfigEntityBase

Buggy or inaccurate documentation? Please file an issue. Need support? Need help programming? Connect with the Drupal community.