kreslitko is a simple environment for drawing graphics in X. Its main aim is to allow writing sequential code in C++ and it performs all event handling operations. It is also able to control running of your program by pressing buttons and filling text entries; it allows you to save drawings in xpm, png, and PostScript format.
Krusader is an advanced twin-panel (commander-style) file-manager for KDE 3.x, but with many extras. It provides all the file-management features you could possibly want. It also features extensive archive handling, mounted filesystem support, FTP, an advanced search module, a text viewer/editor, directory synchronization, support for file content comparisons, powerful batch renaming, and much more. It supports the following archive formats: tar, zip, bzip2, gzip, rar, ace, arj, and rpm. It can also handle other KIOSlaves such as smb:// or fish://.
KVEC is a command line tool that allows you to convert raster graphics to vector graphics. KVEC is designed for 32 bit operating systems and runs on Win32, OS/2, HP-UX, NEXTSTEP, Linux, IRIX, AIX 4.x, Macintosh and BeOS. Docs are available in English and German. The shareware version is available for 30 day trial.
LeoCAD is a CAD application that uses plastic building bricks similar to those found in many toys. This is the Linux port of the original MS Windows version; it uses OpenGL for the graphics and allows the creation of very large/complex models with a library of over 1500 different parts.
libbgrab is a video4linux grabbing library to facilitate use of framegrabber cards and webcams through a few function calls. To implement constant throughput and to avoid frame loss delays, triple buffering is used through local buffer copying in a separate grabbing thread. The many demo and utility programs included can display live video to X, convert live video to ASCII, smoothly zoom live-video (using Glide), do some image processing (using MMX), and provide a stand-alone webcam image server.
libgaudio is a C/C++ library to facilitate easy incorporation of sound and sound effects into games. Samples are loaded into memory and playback is then triggered or stopped. The system mixes any number of concurrently playing samples together (up to a predefined maximum). It is also possible to include a background MP3 soundfile in the mix.