Update libraries in README (#5)

Signed-off-by: Nathaniel Starkman <[email protected]>

profile/README.md

@@ -6,12 +6,13 @@
 
 - [`galax`](https://github.com/GalacticDynamics/galax/): Galactic and Gravitational Dynamics in `JAX`
 - [`coordinax`](https://github.com/GalacticDynamics/coordinax/): Coordinates in `JAX`
-- [`unxt`](https://github.com/GalacticDynamics/coordinax/): Unitful Quantities in `JAX`
+- [`unxt`](https://github.com/GalacticDynamics/unxt/): Unitful Quantities in `JAX`
 
 **Always useful**
 - [`quaxed`](https://github.com/GalacticDynamics/quaxed/): Pre-[`quaxify`](https://docs.kidger.site/quax/)d libraries for use in multiple dispatch over abstract array types in `JAX`
-- [`dataclasstools`](https://github.com/GalacticDynamics/dataclasstools/): tools from [`dataclasses`](https://docs.python.org/3/library/dataclasses.html), extended to all of Python
-- [`immutable_map_jax`](https://github.com/GalacticDynamics/immutable_map_jax): Immutable map (dict), compatible with `JAX` & `equinox`
+- [`dataclassish`](https://github.com/GalacticDynamics/dataclassish/): Tools from [`dataclasses`](https://docs.python.org/3/library/dataclasses.html), extended to all of Python
+- [`xmmutablemap`](https://github.com/GalacticDynamics/xmmutablemap): Immutable map (dict), compatible with `JAX`
+- [`zeroth`](https://github.com/GalacticDynamics/zeroth): Efficiently get the index-0 element of an iterable.
 
 
 ## Ecosystem