How to get a list of entities available in your Drupal? Sometimes I need to create a new entity but I don't know the exact machine name of the entity to put in the entity_create() method.

Is there an easy way to check which entity types are available to create in your Drupal 7 site?
You can just invoke hook_entity_info() and check the keys:

$info = module_invoke_all('entity_info');
$all_entity_machine_names = array_keys($info);