Background pattern 214 #2377
 Blue  CC 0

A seamless chequerboard pattern formed from a tile that can be had in Inkscape by selecting the rectangle and using shift+alt+i.

Source Firkin

 More Textures
45-Degree Fabric@2X #2
 Fabric  CC BY-SA 3.0

Medium gray fabric pattern with 45-degree lines going across.

Source Atle Mo

Decorative divider 217 #2233
 Dark  CC 0

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

Source Firkin

Prismatic Hexagonalist Pattern No Background #390
 Light  CC 0

Prismatic Hexagonalist Pattern No Background

Source GDJ

Tileable Wave Pattern 2 remix #2490
 Dark  CC 0

This is the remix of "Tileable Wave Pattern 2" uploaded by "Arvin61r58".Thanks.I added a wire-mesh fence seamless pattern as a lower layer.

Source Yamachem

Project Papper #119
 Paper  CC BY-SA 3.0

Light square grid pattern, great for a “DIY projects” sort of website, maybe?

Source Rafael Almeida

White carbon@2X #12
 Carbon  CC BY-SA 3.0

Same as the black version, but now in shades of gray. Very subtle and fine grained.

Source Atle Mo

Decorative divider 289 #1819
 Dark  CC 0

From a drawing in 'Navigations de Alouys de Cademoste.-La Navigation du Capitaine Pierre Sintre', Alvise da ca da Mosto, 1895.

Source Firkin

Prismatic Groovy Concentric Background 3 No Black #459
 Noise  CC 0

Prismatic Groovy Concentric Background 3 No Black

Source GDJ

Abstract Arbitrary Geometric Background@2X #498
 Noise  CC 0

Abstract Arbitrary Geometric Background derived from an image on Pixabay.

Source GDJ

Subtle Freckles #89
 Light  CC BY-SA 3.0

This is so subtle: We’re talking 1% opacity. Get your squint on!

Source Atle Mo

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