We have the Rust nursery as a curated library set.
The crates published by the Rust developers themselves seem quite similar to the standard library for this purpose. (But, yes, things like this are not as discoverable as they should be; it is one of many things people are working on.)
Basically, some people like having a curated library set; others do fine without and are happy to find things to use. The former set doesn't like rust as much in its current state.