I am used to using db_select in drupal 7 but now it\'s deprecated in drupal 8
So, If I need to create a query to list all users from users_field_data
table,
Depends on what you are trying to achieve.
If you want to make a simple query about the users then you should use the loadByProperties of the storage object
$users = \Drupal::entityTypeManager()->getStorage('user')->loadByProperties([
'name' => 'bar'
]);
If you need a more complex query with sorts, range, pager and OR/AND condition groups you should use entity query
$ids = \Drupal::entityQuery('user')->condition('name', 'foo')->execute();
$users = User::loadMultiple($ids);