Get a list of available migration destination plugins
With Drupal Console:

$ drupal debug:plugin migrate.destination


Or short:

$ drupal dpl migrate.destination


gives:

------------------------------------------ --------------------------------------------------------------------------------------- 
  Plugin ID                                  Plugin class                                                                           
 ------------------------------------------ --------------------------------------------------------------------------------------- 
  component_entity_display                   Drupal\migrate\Plugin\migrate\destination\PerComponentEntityDisplay                    
  component_entity_form_display              Drupal\migrate\Plugin\migrate\destination\PerComponentEntityFormDisplay                
  config                                     Drupal\migrate\Plugin\migrate\destination\Config                                       
  d7_theme_settings                          Drupal\system\Plugin\migrate\destination\d7\ThemeSettings                              
  entity:action                              Drupal\migrate\Plugin\migrate\destination\EntityConfigBase                             
  entity:base_field_override                 Drupal\migrate\Plugin\migrate\destination\EntityBaseFieldOverride                      
  entity:block                               Drupal\block\Plugin\migrate\destination\EntityBlock                                    
  entity:block_content                       Drupal\migrate\Plugin\migrate\destination\EntityContentBase                            
  entity:block_content_type                  Drupal\migrate\Plugin\migrate\destination\EntityConfigBase                                                        
  entity:comment                             Drupal\comment\Plugin\migrate\destination\EntityComment                                
  ...          

With drush:

$ drush php
&gt;&gt;&gt; array_keys(\Drupal::service('plugin.manager.migrate.destination')-&gt;getDefinitions());


gives:

=&gt; [
 "entity:block",
 "entity:comment",
 "entity:comment_type",
 "d7_field_group",
 "field_group_entity_form_display",
 "field_group_entity_view_display",
 "entity:file",
 ...
]