1. Nexus Mod Manager (was known as Fallout Mod Manager)- Manages your mods with some abilities of the programs listed below 2. GECK- The actual program used to make mods 3. FO3Edit- A program that allows you to merge mods together to make a seamless patch so that they work together. 4. O3Plugin- Same as FO3Edit, but is more simple to use. 5. FO3Archive- Specifically deals with archived .BSA files and will even work with Morrowinds .BSA files....- so pretty much, it extracts what's in the .BSA file you opened so you can get a certain texture or Model from a mod.