White Paperboard #374
 Fabric  CC BY-SA 3.0

Could be paper, could be a Polaroid frame – up to you!

Source Chaos

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

Sort of like the Photoshop transparent background, but better!

Source Alex Parker

Floral design 71 #2429
 Dark  CC 0

From a drawing in 'From Snowdon to the Sea. Striking stories of North and South Wales', Marie Trevelyan, 1895.

Source Firkin

Prismatic Triangular Seamless Pattern III With Background #273
 Dark  CC 0

Prismatic Triangular Seamless Pattern III With Background

Source GDJ

Background pattern 9 (greyscale) #213
 Dark  CC BY-SA 3.0

Greyscale version of a pattern that came out of playing with the 'light rays' plug-in for Paint.net

Source Firkin

Prismatic Dots Background 6 #511
 Dark  CC 0

Prismatic Dots Background 6

Source GDJ

Seamless Core Pattern #165
 Dark  CC 0

Seamless Core Pattern

Source GDJ

Dark Circles #306
 Dark  CC BY-SA 3.0

People seem to enjoy dark patterns, so here is one with some circles.

Source Atle Mo

Prismatic Rounded Squares Grid 4 No Background@2X #492
 Noise  CC 0

Prismatic Rounded Squares Grid 4 No Background

Source GDJ

Felt #300
 Wall  CC BY-SA 3.0

Got some felt in my mailbox today, so I scanned it for you to use.

Source Atle Mo

Background pattern 225 (colour 3) #2325
 Pink  CC 0

Seamless pattern formed from a tile that can be extracted by selecting the rectangle in Inkscape and using shift-alt-i.

Source Firkin

polka dot seamless pattern remix 02 #2495
 Pink  CC 0

This is the remix of "polka dot seamless pattern".The image depicts polka dot seamless pattern.

Source Yamachem

Background pattern 306 #1882
 Colorful  CC 0

Seamless pattern the tile for which can be had by using shift-alt-I on the selected rectangle in Inkscape.

Source Firkin