Checkered Light Emboss #280
 Grid  CC BY-SA 3.0

Sort of like the Photoshop transparent background, but better!

Source Alex Parker

 More Textures
Prismatic Geometric Tessellation Pattern No Background #551
 Noise  CC 0

Prismatic Geometric Tessellation Pattern No Background

Source GDJ

Carbon Fiber v2 #105
 Carbon  CC BY-SA 3.0

One more updated pattern. Not really carbon fiber, but it’s the most popular pattern, so I’ll give you an extra choice.

Source Atle Mo

Shapes pattern #2409
 Brown  CC 0

A seamless pattern formed from a square tile. The tile can be retrieved by selecting the rectangle in Inkscape and using shift-alt-i.

Source Firkin

Background pattern 223 (colour 2) #2352
 Blue  CC 0

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

Source Firkin

Diagonal Noise #181
 Fabric  CC BY-SA 3.0

A simple but elegant classic. Every collection needs one of these.

Source Christopher Burton

3px Tile@2X #343
 Dark  CC BY-SA 3.0

Tiny dark square tiles with varied color tones.

Source Gre3g

Mosaic tile #2481
 Brown  CC 0

From a drawing in 'Handbook of the excursions proposed to be made by the Lincoln Diocesan Architectural Society, on the 27th and 28th of May, 1857', Edward Trollope, 1857.

Source Firkin

Colourful background #2007
 Colorful  CC 0

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

Source Firkin

Leather 1@2X #14
 Light  CC BY-SA 3.0

A leather pattern with a hint of yellow.

Source Atle Mo

Prismatic Polka Dots Mark II 2 No Background #532
 Noise  CC 0

Prismatic Polka Dots Mark II 2 No Background

Source GDJ

Decorative divider 218 #2232
 Dark  CC 0

Remixed from a drawing in 'Maidenhood; or, the Verge of the Stream', Laura Jewry, 1876.

Source Firkin

Decorative divider 192 #2503
 Dark  CC 0

From a drawing in 'Worsborough; its historical associations and rural attractions', Joseph Wilkinson, 1879.

Source Firkin