Homeworld Tools Section
3D Exploration incl. 3DS Max & Maya Plugins - A tool to view and edit models and textures in Homeworld. As far as I know, this was the last release before Right Hemisphere changed the product.
Background Tool of the Geeks - For creating backgrounds in maps. 
Homeworld Bigviewer 3 by Talisin - For opening and extracting the contents of the Homeworld .big file. 
FEMan (Homeworld Front End Manager) - The tool that was used to modify the Homeworld Interface (GUI). You can use it to create custom interfaces.
Homesong - A tool to extract the aifr audio from Homeworld
Homeworld Source Code - This is the Homeworld source code and and documentation, stripped of code not owned by Relic Entertainment.
Homeworld Unit Viewer - Allows you to view the ships from Homeworld outside of the game itself. Here you can zoom, rotate, take screenshots, alter colour schemes, and find information about the ships. This file includes all the ships released and the viewer itself.
Homeworld Video Tweaker - Allows you to alter the graphical settings of Homeworld which they didnt include in the actual game. Owners of more modern graphics cards may want to give this a try to get the best looks from Homeworld. I believe it also works for Cataclysm. Basically you put it in your Homeworld or Cataclysm directory and open it. It then alters a file called Devstats.dat.
HWSE (Homeworld Ship Editor) - An invaluable tool for serious HW modders by Delpy. 
Liflist - DOS program for formatting PSD textures to work in Homeworld.
Modman 5.1 (Mod Manager) - A modification manager that allows you to categorise your mod collection and quickly add or remove a mod with minimal effort. Once placed in the right directory and with a few settings adjusted, modman will have you switching between mods in no time! Supports Homeworld and Cataclysm.
Relic AIFR Winamp Plugin - Allows Winamp 2 or above to play the .aifr audio file format used for the music in Homeworld. 
Spooky's Relic Archive Tool v2.00 - A tool to open the .big files of Homeworld, Homeworld 2, Impossible Creatures and Dawn Of War. 
TBS's Homeworld Launcher - A configurator by TheBlessedSheridan which allows the user to execute the Homeworld EXE with various command switches which add functionality or troubleshooting logs to Homeworld.
Winbig - The classic Winbig for opening and creating .big files compatible with Homeworld. 
Winbigr - A recently released modern version of Winbig. 
Winbigw - A recently released modern version of Winbig.

Homeworld 2 Tools Section
MissionBoySE 1.9 - A tool for creating maps in Homeworld 2 by the legendary Delpy.