An implementation of OpenGL 3.x-ish in clean C

Unintrusive algorithms for C arrays OR a C implementation of <algorithm> from C++

Single-header LZW (Lempel-Ziv-Welch) C Library, headerless compressor & decompressor (variable code, 9-16 bits)

Super small, simple, and (almost) completely C89-compliant single-header arena "allocator".

Cex.C - Comprehensively EXtended C Language

A single file, freestanding FLAC encoding library in C89

A single-file FLAC encoding library

Luamalg – Lua 5.4.7 core, libraries and interpreter in a single header file.

Various single header libraries in C

A very fast SIMD (AVX2) accelerated lexer that does not rely on tables

A simple, single-header library which implements defer and autofree at compile-time in C/C++

A single-file ALAC encoder (that doesn't actually compress)

The World's First, Only & Most Amazing RLE Zoo

PicoTest is a single-file unit testing framework for C programs that follows the xUnit principles.

Single-header library for memory menagement

Single-file FLAC decoder with a push-style API

A single header C library for parsing and deserializing CSV buffers

An *single-header* alternative, pure C-focused wrapper to Apple's Cocoa API for OS X app development. Requires little to no Objective-C knowledge to use. Based on the original Silicon by EimaMei! Written in Pure C, no objective-c nonsense.

Single header Parameterised testing and mocking library C/C++

Tool / DSL to prefix and package C source code