Greg's Factory Output Filters  
Great set of free filters being hosted by State of Entropy (scroll down page).
Greg's Pool Shadow is a very popular filter.

Harry's Filters   
Free filters, great one's too
Video Rave, Harry's Power Grads, Cryptology and Nirvana

Hemera Photo-Objects Collections  
Free demo available.
Photo images with transparent backgrounds. Excellent. 

Impression X  
Program with many uses, including "Paint By Numbers"

HotFreeware   
20/20
Program to make Seamless Tiles

Tutorial for Paper Texture Backgrounds

Huey 1.9 Freeware  
HTML color generator that converts RGB values to Hex and from Hex back to RGB, or picks directly from any part of the screen with the Color Pipette feature. IrfanView  
Freeware Graphic viewer
Excellent program

Infinity Textures   
Image based texture designer and generator