STK Simple ToolKit

www.free86.org - X Window System

GCC GNU C Compiler

SDL Simple Directmedia Layer library

GGI General Graphics Interface

DirectFB Graphics library using frame buffer

FBUI Frame Buffer User Interface

FLTK Fast and Light ToolKit project page

GTK Gimp ToolKit project page

Qt Qt toolkit project page

FOX toolkit Fox GUI toolkit, c++, X11/Win32

aedGUI Cross-platform, easy to use, c++ GUI based on SDL

GLO Platform independent GUI library for games

GraphApp multiplatform GUI for X11/Mac/Win32, c/c++

LGI Lightweight GUI Interface, SDL/Glut based, Linux/Win32/BeOS

libUFO UI for OpenGL, c++, SDL/Glut based,

Lit Lit Window Library, c++, easy to make UI

LiteClue Widget bubble/baloon help X widget

ParaGUI cross-platform GUI, SDL based

sjgui OpenGL GUI, very easy and fast development

TOAD GUI Simple c++ GUI toolkit for X11

V GUI, c++ for X11 and OS/2

AbsoluteX free classed for X11, uses libsigc++

Xlib programming - very good Xlib manual from "choo", 2 parts

??? - online Xlib man pages in html form