Seamless Core Pattern 5 #169
 Dark  CC 0

Seamless Core Pattern 5

Source GDJ

 More Textures
Always Grey #53
 Dark  CC BY-SA 3.0

Crossing lines with a subtle emboss effect on a dark background.

Source Stefan Aleksić

Floral background 20 #1813
 Red  CC 0

Derived from a drawing in 'Elfrica. An historical romance of the twelfth century', Charlotte Boger, 1885

Source Firkin

Prismatic Hexagonalism Pattern No Background #391
 Light  CC 0

Prismatic Hexagonalism Pattern No Background

Source GDJ

Candyhole #356
 Light  CC BY-SA 3.0

It’s a hole, in a pattern. On your website. Dig it!

Source Josh Green

Prismatic Groovy Concentric Background 4 #461
 Noise  CC 0

Prismatic Groovy Concentric Background 4

Source GDJ

Small Crosses@2X #116
 Stripes  CC BY-SA 3.0

Sharp pixel pattern looking like some sort of fabric.

Source Dmitry

Prismatic Groovy Concentric Background 5 No Black #467
 Dark  CC 0

Prismatic Groovy Concentric Background 5 No Black

Source GDJ

Prismatic Basic Pattern 2 No Background #447
 Noise  CC 0

Prismatic Basic Pattern 2 No Background

Source GDJ

Background pattern 201 (colour 4) #2494
 Grid  CC 0

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

Source Firkin

Axiom Pattern@2X #331
 Grid  CC BY-SA 3.0

Not even 1kb, but very stylish. Gray thin lines.

Source Struck Axiom