Here are implementations of diverse data structures in some different languages. Each major data structure is organized in its directory, with each variation of the data structure with its own directory, containing a directory for each of the languages that data structure is implemented in. There might be an implementation of the major data structure in an abstract way, like with binary trees.
I started this project as a way of having a deeper understanding of data structures, of how they work, how I can improve them, and a better understanding of the differences between various languages.