Pre-production Software

Celtx
Directors Boards Free 2.0a
Scriptbuddy
StoryBoard Pro

Software Plug-ins

Final Cut:
Pistolerapost.com Final Cut Plug-ins
Two Strip Technicolor
Three Strip Technicolor
Three Strip Extreme
Richer
Convolve Toy
Captain's Blowout Fixer
Luma Toy

AfterEffects Flame
AeFlame is an Adobe After Effects plug in that allows you to create and animate cosmic recursive flame fractals.

Vinyl
Vinyl is an audio plugin for simulating lo-fi sources

CoreMelt Free Plugins
Image Flow: The trial version of ImageFlow Fx for After Effects includes three free plugins which do not have any expiry or watermark, Carousel, Continuous Random Pan and ImageFilmstrip (For AfterEffects, Final Cut Pro, Final Cut Express, and Motion)

VeeYou Free Plugins: A completely free pack of eight plugins to generate VU and EQ animations from the audio in your Final Cut Studio project. Choose from old school analog dials or modern slick LED Eqs. Instantly create graphic elements for music videos or promos that automatically sync to your audio. (For AfterEffects, Final Cut Pro, Final Cut Express, and Motion)

PolyChrome Free Plugins: CoreMelt PolyChrome Transition pack contains 5 plugins which are completely free. Blend Mode Dissolve, Curl Apart, Exposure Flash, Projector Malfunction, Random Crop (For Final Cut Pro, Final Cut Express, and Motion)

Rebel-CC
An After Effects Animation Preset for color grading.

New Blue Cartoonr
Simulates hand drawn cartoons.
Download.com
Contains many helpful free downloads for video players and conversion tools. {Perhaps we pull this one apart and grab excellent things like VLC into their own link?}

Audio Editors

Ardour (audio processor)+
Audacity
BashPodder
CD-DA X-Tractor
CDex
Grip audio ripper
JACK Audio Connection Kit
Jokosher
Linux MultiMedia Studio
MusE
OpenSebJ
Pure Data
Rosegarden
Streamripper
SoX

2D animation

KToon
Synfig
Pencil

Pre-production Software

Software Plug-ins

Audio Editors

2D animation

Video editing

3d graphics software packages

Photo Editing Software