C++ Standard (ISO/IEC 14882)

1. Language

   Language reference: declarations, expressions, classes and templates.

2. Templates

   Template syntax, specialization and variadic templates.

3. Constants and the memory model

   Object lifetime, bit-fields and the memory model.

4. Containers library

   vector, map, unordered_map and other containers.

5. Algorithms library

   Non-modifying, modifying and sorting algorithms.

6. Iterators and ranges

   Range adaptors and views in C++20.

7. Dynamic memory management

   Smart pointers unique_ptr, shared_ptr and allocators.

8. Concurrency support

   Threads, mutexes, futures and atomics.

9. Concepts

   Constraints and concept library of C++20.

10. Coroutines

    co_await, co_yield, co_return and promise types.

11. Utilities library

    pair, tuple, optional, variant and move semantics.

12. Strings library

    std::string, string_view and formatting.

Each section links to the official page. Titles and summaries by Extra Credit; the docs belong to their authors.