lib-x/xstr | A simple public domain string library | String manipulation | Unlicense |

yrmt/arraylist | doubly linked list based on BSD TAILQ | Data structure | MIT |

clibs/list | simple doubly linked list | Data structure | MIT |

troydhanson/uthash | C macros for hash tables and more | Data structure | Unlicensed |

willemt/farraylist | An arraylist that doesn't shift items so you can have "holes" between slots | Data structure | BSD |

ajaymt/list.c | Simple linked list | Data structure | MIT |

clehner/ll.c | Transparent linked lists | Data structure | LGPL-3.0+ |

kellydunn/libkld | Personal implementations of common datastructures. (List, Vector, Graph, Matrix, Tree, etc) | Data structure | Unlicensed |

neylsongularte/simple-linked-list-c | Linked list implementation | Data structure | Unlicensed |

arablocks/flat-tree.c | A series of functions to map a binary tree to a list ported from flat-tree. | Data structure | MIT |