Joe's Filters 3.5 http://www.joesfilters.com/

Sold as a pack. Working Demos Available.Joe Maller has written a most useful set of filters (33 of 'em, at last count) available for FCP. All Hail Joe!

You get an arsenal of effects:

• Adjustments - Levels, Sampled Color Levels, Saturation & Colorize, Simple Saturation, Threshold & Posterize
• Alpha Effects - Bevel & Emboss, Drop Shadow, Inner Shadow
• Blur Filters - Channel Blur, Diffuser, Motion Blur
• Noise Filters - Color Noise, Levels Noise, Noise Reducer, Saturation Noise
• Soft Stuff - Soft Ellipse, Soft Gradients, Soft Spot, Soft Shapes
• Stylize Filters - Color Glow, Flexi-Smear, Gradients, Maximizer, Pixelizer
• Video & Time Filters - Broadcast Legalizer, De-Interlacer, Field Blender, Field Fixer, Frame Rate Adjuster, Multi-Frame Blender, Time Bender
• Generators - Ellipse, Shapes

They're great value for money, practical, open-source and very well documented.

Joe has made his detailed FXscript reference into a public resource:
http://www.fxscriptreference.org/.