How do I get all ContentEntities? What I'm trying to do is 

$entities = EntityInterface::loadMultiple();


That should give me all entities.

But when I call it, it gives me this


  Fatal error: Cannot call abstract method Drupal\Core\Entity\EntityInterface::loadMultiple() 


What I need is the type and the bundles of the entities.

I don't want to get specific entities like Node, Comment, Block etc. I want to get them all.

$fields['node']['article'] =  &lt;&lt;&lt;&lt; I want that dynamic.


Something like that 

foreach($entities as $entity) {
  $fields[$entity-&gt;getType()][$entity-&gt;bundle()] = ....
}
You can get around the error about the abstract method by using entity::loadMultiple, but you'll get a new error, because this only works from an entity subclass.

Instead of using the static method, you would have to do this dynamically:

First get all content entity types:

  $entity_types = \Drupal::entityTypeManager()-&gt;getDefinitions();
  $content_entity_types = array_filter($entity_types, function ($entity_type) {
    return $entity_type instanceof \Drupal\Core\Entity\ContentEntityTypeInterface;
  });
  $content_entity_type_ids = array_keys($content_entity_types);


Then load all entities for each type:

  $entities = [];
  foreach ($content_entity_type_ids as $type) {
    $entities[$type] = \Drupal::entityTypeManager()-&gt;getStorage($type)-&gt;loadMultiple();
  }