All classes that implement CKEditorPluginConfigurableInterface

class \Drupal\ckeditor\Plugin\CKEditorPlugin\StylesCombo implements CKEditorPluginConfigurableInterface
class \Drupal\ckeditor_test\Plugin\CKEditorPlugin\LlamaContextualAndButton implements CKEditorPluginButtonsInterface, CKEditorPluginConfigurableInterface, CKEditorPluginContextualInterface