Many programming langauges (such as Python and Go) take a "kitchen sink" approach to their standard libraries, including functionality like regular expressions, random number generation, serialization (JSON, XML, etc), and HTTP clients and servers directly in the stdlib.
The standard library in Rust is much smaller than in Python or Go, for example. Those languages come with "batteries included" support for things like HTTP(S), JSON, timezones, random numbers, and async IO. Rust, on the other hand, gets things like that from the crates.io ecosystem and the Cargo package manager. But with almost 100 thousand crates to choose from, a common complaint from new Rust developers is that they don't know where to start, which crates they ought to use, and which crates they ought to
See also lib.rs which takes a more automated approach (ordering crates by number of downloads) and also has an excellent search function.