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

https://git.adelielinux.org/community/a52dec/

Advanced Access Content System implementation

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

Building blocks for modern GNOME applications

https://www.gtk.org/

Adaptive entropy coding library

https://gitlab.dkrz.de/k202009/libaec https://github.com/MathisRosenhauer/libaec

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

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

Portable audio output library

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

KSNI App Indicator library

https://launchpad.net/libappindicator

Generic Apache2 Request Library

https://metacpan.org/dist/libapreq2

Library to create and read several streaming archive formats

https://libarchive.org/

Memory hard password hashing program and library

https://github.com/P-H-C/phc-winner-argon2

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

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

Library for encoding and decoding .avif files

https://github.com/AOMediaCodec/libavif

Ayatana Application Indicators Shared Library

https://github.com/AyatanaIndicators/libayatana-appindicator

Ayatana Indicators Shared Library

https://github.com/AyatanaIndicators/libayatana-indicator

Library for fast Base64 encoding and decoding

https://libb64.sourceforge.net/

Library and tools to access the BitLocker Drive Encryption volumes

https://github.com/libyal/libbde

BD+ System research implementation

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

Standard C resolver library

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

Blu-Ray discs playback library for media players

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

Bauer Stereophonic-to-Binaural DSP

https://bs2b.sourceforge.net/

Libburnia library to read/write optical discs

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

Graphics library that outputs text instead of pixels

http://caca.zoy.org/

Library to support cross-platform AES encryption

https://github.com/libyal/libcaes

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/

Implementation of the Freedesktop sound theme spec

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

CBOR protocol implementation for C and others

https://github.com/PJK/libcbor

Generic driver for USB CCID and ICCD

https://ccid.apdu.fr/

Library for playing audio CDs

https://libcdaudio.sourceforge.net/

Library to access data on a CDDB server

https://libcddb.sourceforge.net/

Compact Disc Input and Control Library

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

Read audio from the CDROM directly as data

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

Library and tools for parsing Corel Draw file format

https://wiki.documentfoundation.org/DLP/Libraries/libcdr

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

Ultralightweight JSON parser in ANSI C

https://github.com/DaveGamble/cJSON

Required library functions for OpenCL C programming language

https://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/

Library for accessing the MusicBrainz cover art archive

https://coverartarchive.org/

CSS2 parsing library

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

GNOME application for managing encryption keys (PGP, SSH)

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

Cascading Style Sheets library

https://www.netsurf-browser.org/projects/libcss/

CUE Sheet Parser Library

https://github.com/lipnitsk/libcue

Lightweight C library that eases the writing of UNIX daemons

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