Объединить две коллекции
$users = User::all();
$associates = Associate::all();
$userAndAssociate = $users->concat($associates);
Irfan
$users = User::all();
$associates = Associate::all();
$userAndAssociate = $users->concat($associates);
$users = User::all();
$associates = Associate::all();
$userAndAssociate = $users->concat($associates);