Background pattern 314 #1839
 Yellow  CC 0

The square tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i

Source Firkin

 More Textures
Psychedelic Geometric Background #381
 Noise  CC 0

Psychedelic Geometric Background.

Source GDJ

Whitey #109
 Light  CC BY-SA 3.0

A white version of the very popular linen pattern.

Source Ant Ekşiler

Floral design 100 (version 2, colour) #1772
 Green  CC 0

From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.

Source Firkin

Colourful background #2010
 Colorful  CC 0

Made by distorting a simple pattern using the 'sin waves' plugin for Paint.net and vectorising in Vector Magic

Source Firkin

Pool Table@2X #176
 Wall  CC BY-SA 3.0

This makes me wanna shoot some pool! Sweet green pool table pattern.

Source Caveman

Checkered Light Emboss@2X #281
 Grid  CC BY-SA 3.0

Sort of like the Photoshop transparent background, but better!

Source Alex Parker

Seamless Prismatic Geometric Pattern With Background #264
 Dark  CC 0

Seamless Prismatic Geometric Pattern With Background

Source GDJ

Fancy Deboss@2X #178
 Fabric  CC BY-SA 3.0

Luxury pattern, looking like it came right out of Paris.

Source Daniel Beaton

White Texture #131
 Light  CC BY-SA 3.0

Not the most creative name, but it’s a good all-purpose light background.

Source Dmitry

Handmade Paper #37
 Paper  CC BY-SA 3.0

White handmade paper pattern with small bumps.

Source Marquis

Medic Packaging Foil@2X #377
 Light  CC BY-SA 3.0

8 by 8 pixels, and just what the title says.

Source pixilated

Clover with background #237
 Paper  CC 0

Clover with background for St. Patrick's Day. Add to a card with a doily, ribbon, a leprechaun or other embellishments.

Source BAJ

Prismatic Isometric Cube Wireframe Pattern No Background@2X #500
 Light  CC 0

Prismatic Isometric Cube Wireframe Pattern No Background

Source GDJ