indoc (indented/formatted multi line string literals)
strum (various derive macros for enums)
petgraph (for working with general graphs)
winnow is a great (and fast) parser combinator library.
bpaf, clap and xflags are three different command line argument parser libraries. Which one to use depends on the needs of the project and if you need to match the behaviour of an existing non-rust program (as I needed to in one case)
This is the first time I'm hearing about blessed.rs, thank you. Havent used lib.rs since they closed the source. Thanks for sharing.
I wrote a string case conversion library called "convert-case". Most people use "heck". They use different patterns, and different naming conventions. I prefer mine (more features), but it also came out long after heck became standard.
Here is an originally random list (using cargo tree --prefix=depth) with some very loose logical grouping. Wide-scoped and well-known crates removed (some remaining are probably still known by most).