std
std::allocator
std::array
std::atomic
std::atomic_ref
std::auto_ptr
std::bad_alloc
std::bad_cast
std::bad_exception
std::bad_typeid
std::basic_fstream
std::basic_ifstream
std::basic_ios
std::basic_iostream
std::basic_istream
std::basic_istringstream
std::basic_ofstream
std::basic_ostream
std::basic_ostringstream
std::basic_string
std::basic_string_view
std::basic_stringstream
std::bitset
std::complex
std::deque
std::domain_error
std::error_category
std::error_code
std::error_condition
std::exception
std::forward_list
std::fstream
std::ifstream
std::invalid_argument
std::ios
std::ios_base
std::istream
std::istringstream
std::jthread
std::length_error
std::list
std::lock_guard
std::logic_error
std::map
std::multimap
std::multiset
std::mutex
std::ofstream
std::ostream
std::ostringstream
std::out_of_range
std::overflow_error
std::priority_queue
std::queue
std::range_error
std::recursive_mutex
std::recursive_timed_mutex
std::runtime_error
std::set
std::shared_lock
std::shared_mutex
std::shared_ptr
std::shared_timed_mutex
std::smart_ptr
std::span
std::stack
std::string
std::string_view
std::stringstream
std::system_error
std::thread
std::timed_mutex
std::u16string
std::u16string_view
std::u32string
std::u32string_view
std::u8string
std::u8string_view
std::underflow_error
std::unique_lock
std::unique_ptr
std::unordered_map
std::unordered_multimap
std::unordered_multiset
std::unordered_set
std::valarray
std::vector
std::weak_ptr
std::wfstream
std::wifstream
std::wios
std::wistream
std::wistringstream
std::wofstream
std::wostream
std::wostringstream
std::wstring
std::wstring_view
std::wstringstream

STL namespace.