Colliflower is a library for abstaractions around data structures. It includes three sub-libraries:

tools for iterating using an iterator closure. Provides function similar to python's itertools and macros and iterate directives to iterate over such iterators easily.
library for building data structures. It is a generalization of the collecting macro, where you can efficiently build other kinds of data structures.
library for accessing, setting, and deleting values by some key. similar to access

The library comes with implementations for lisps built in data structures (list, array, hash-table, etc.) but can also be extended to other data structures such as those in cl-containers or lisp-interface-library.