X Render extension library

http://www.freedesktop.org/Software/xlibs

X Resource usage library

http://www.freedesktop.org/Software/xlibs

X Toolkit library

https://www.freedesktop.org/wiki/Software/xlibs/

X Test extension

http://www.freedesktop.org/Software/xorg

X Video Extension library

http://www.freedesktop.org/Software/xlibs

X Video Extension Motion Compensation library

https://www.freedesktop.org/wiki/Software/xlibs/

X DGA Extension

http://www.freedesktop.org/Software/xorg

X XF86-Misc Extension

http://www.freedesktop.org/Software/xorg

X Vidmode Extension

http://www.freedesktop.org/Software/xorg

Free library for decoding ATSC A/52 streams, aka AC-3

http://liba52.sourceforge.net/

HE-AAC+ Codec as Shared Library

http://tipok.org.ua/node/17/

3GPP Adaptive Multi-Rate - Wideband (AMR-WB) Speech Codec

http://www.penguin.cz/~utx/amr

Portable audio output library

https://www.xiph.org/ao/

Library to create and read several streaming archive formats

https://libarchive.org/

Library for high-performance 2D graphics

http://www.levien.com/libart/

Portable ASS/SSA subtitle renderer

https://github.com/libass/libass

IPC library used by GnuPG and gpgme

https://gnupg.org/related_software/libassuan/index.en.html

Atomic operations access library

https://github.com/ivmai/libatomic_ops

Sound library for SGI audio file

http://www.68k.org/~michael/audiofile/

Standard C resolver library

https://www.isc.org/software/libbind

Component and compound document system for GNOME2

http://www.gnome.org/

GUI frontend to the libbonobo component of GNOME 2

http://www.gnome.org/

Libburnia library to read/write optical discs

https://dev.lovelyhq.com/libburnia/web/wikis/home

LLVM C++ standard library with c++11 support

http://libcxx.llvm.org/

Graphics library that outputs text instead of pixels

http://caca.zoy.org/

Implementation of the Freedesktop sound theme spec

https://0pointer.de/lennart/projects/libcanberra/

Implementation of the Freedesktop sound theme spec

https://0pointer.de/lennart/projects/libcanberra/

Library for playing audio CDs

http://libcdaudio.sourceforge.net/

Library to access data on a CDDB server

http://libcddb.sourceforge.net/

Compact Disc Input and Control Library

http://www.gnu.org/software/libcdio/

Read audio from the CDROM directly as data

http://www.gnu.org/software/libcdio/

C library aimed to provide a Gtk+ widget to display rasterized maps and markers

http://projects.gnome.org/libchamplain/

Tool to check shared library links

http://svn.idaemons.org/cgi-bin/viewvc.cgi/trunk/?root=libchk

Required library functions for OpenCL C programming language

http://libclc.llvm.org/

Alternative configuration system for Compiz

Simple library for manipulating structured configuration files

https://www.hyperrealm.com/libconfig/libconfig.html

Configuration file parsing library

http://savannah.nongnu.org/projects/confuse/

CSS2 parsing library

http://www.freespiders.org/projects/libcroco/

GNOME application for managing encryption keys (PGP, SSH)

https://gitlab.gnome.org/GNOME/libcryptui

CUE Sheet Parser Library

https://github.com/lipnitsk/libcue

Implementation of the Code Sourcery C++ ABI

https://github.com/pathscale/libcxxrt

Lightweight C library that eases the writing of UNIX daemons

http://0pointer.de/lennart/projects/libdaemon/

Double-array trie implementation library

https://linux.thai.net/projects/datrie/

Free DTS Coherent Acoustics decoder

https://www.videolan.org/developers/libdca.html

Generic Device Query and Monitor interface

https://github.com/freebsd/libdevq

Library for creating MusicBrainz DiscIDs

http://musicbrainz.org/doc/libdiscid

Library for reading and writing Data Matrix barcodes

http://libdmtx.sourceforge.net/

DMX extension library

http://www.freedesktop.org/Software/xorg

Simple interface to low level networking routines

https://github.com/5u623l20/libdnet/

Standard library for Window Maker dock apps

http://solfertje.student.utwente.nl/~dalroi/libdockapp/