OpenDarwin XML eXtensible ARchiver

http://mackyle.github.io/xar/

X authority file utility

TV viewing application and a few TV utilities

https://linuxtv.org/

Program to adjust backlight brightness

Motif-based widget which displays a grid of cells as a spreadsheet

http://xbae.sourceforge.net/

Mailbox flag for X

X.Org bitmaps data

Brightness and gamma correction through the X server

http://disjunkt.com/xbrightness/

High-performance low-overhead BitTorrent tracker

https://xbtt.sourceforge.net/

Replacement for xbiff that handles multiple mail files

Scientific calculator for X

Calendar with a notebook for X11 (internationalized version)

Tool for managing x11 cut-buffers

http://oldhome.schmorp.de/marc/xcb.html

Input method development support for XCB

https://github.com/fcitx/xcb-imdkit

The X protocol C-language Binding (XCB) protocol

https://xcb.freedesktop.org/

Module with libxcb/libX11 extension/replacement libraries

https://xcb.freedesktop.org/

XCB cursor library

https://xcb.freedesktop.org/

Pretty-print XCB codes

https://xcb.freedesktop.org/

Port of Xlib's XImage and XShmImage functions

http://xcb.freedesktop.org/

Standard X key constants and conversion to/from keycodes

http://xcb.freedesktop.org/

Convenience functions for the Render extension

https://xcb.freedesktop.org/

Framework for window manager implementation

http://xcb.freedesktop.org/

XCB utility functions for the X resource manager

https://github.com/Airblader/xcb-util-xrm

X11 circuit schematics drawing program

http://opencircuitdesign.com/xcircuit/

Exciting Cite for any Mail/News reading modes on Emacs

https://www.gentei.org/~yuuji/software/

Interface to X selections ("the clipboard") from the command line

https://github.com/astrand/xclip

X clipboard client

Analog and digital clock for X

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

Device Color Characterization utility for X

Sample X compositing manager

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

MidnightBSD X configuration tool

https://github.com/midnightbsd/xconfig

Monitor system console messages with X

Multiwindow mouse-based text editor for X

http://xcoral.free.fr/

X.org cursors themes

Create an X cursor file from a collection of PNG images

Rather neat animated clock (GL & GTK version)

https://www.jwz.org/xdaliclock/

Rather neat animated clock (Xlib version)

https://www.jwz.org/xdaliclock/

Sets the background of your X desktop under water

http://xdesktopwaves.sourceforge.net/

X11 program for uu/xx/Base64/BinHex/yEnc de-/encoding

http://www.fpx.de/fp/Software/UUDeview/

Portal frontend service for Flatpak

https://github.com/flatpak/xdg-desktop-portal/

Backend implementation for xdg-desktop-portal for GNOME

https://gitlab.gnome.org/GNOME/xdg-desktop-portal-gnome

Gtk implementation of xdg-desktop-portal

https://github.com/flatpak/xdg-desktop-portal-gtk

xdg-desktop-portal backend for hyprland

https://github.com/hyprwm/xdg-desktop-portal-hyprland

Command line interface to launch graphical terminal applications

https://gitlab.freedesktop.org/terminal-wg/specifications/-/merge_requests/3

Tool to help manage personal user directories

https://freedesktop.org/wiki/Software/xdg-user-dirs/

Gtk+ integration of special directories

https://gitlab.gnome.org/GNOME/xdg-user-dirs-gtk

Tools to allow all applications to integrate with the free desktop

https://www.freedesktop.org/wiki/Software/xdg-utils/

Display ditroff output

X.Org X display manager

Tool for decompressing Amiga DMS files

https://zakalwe.fi/~shd/foss/xdms/