Would be awesome to have something like a Trait Encyclopedia.
Not sure exactly how it would be built, or what the search options would look like... but I think as one gets more comfortable with the basic syntax and properties of Rust, the question of "Is there a trait that does x" or "I keep seeing this trait x everywhere, what's it used for" keeps coming up when moving from say a fresh beginner to a beginner/intermediate level.
The Haskell Typeclassopedia could be good for inspiration... not necessarily for the content but for the concept. In other words - not just looking at each trait from one angle of signature+description, but from multiple angles... "what problem it solves", "how it's different from similar traits", etc.
Just putting this out there in case anyone is looking for something to do