The Rust standard library, indexed.

HashMap, BTreeMap, Vec, VecDeque — every general-purpose container in std.

The Iterator trait, adapters, and consumers — Rust's lazy zero-cost pipelines.

Read, Write, BufReader, BufWriter — synchronous byte-stream plumbing.

Files, directories, metadata, atomic-write helpers and path traversal.

Mutex, RwLock, Arc, atomics, channels — all the cross-thread primitives.

Native OS threads, scoped joins, thread-local storage, and parking.

Option<T> — Rust's null-free representation of "value may be absent".

Result<T, E> — fallible operations as values, with the ? operator.

UTF-8 string slices: searching, splitting, parsing, iteration.

The growable contiguous heap-allocated array — Rust's default sequence.

Display, Debug, Formatter — the traits behind every format string.

Process environment: args, vars, current_dir, and the env! macro.

Spawning subprocesses, capturing output, and managing exit status.

TcpStream, TcpListener, UdpSocket — synchronous network I/O.

Instant, Duration, SystemTime — measuring and waiting.

All 305,250 published crates, alphabetically, 200 per page.

103 crates.io categories, from algorithms to WebAssembly.

Example crate profile page — metadata, license, links.