Fabric pattern (colour 5) #2398
 Fabric  CC 0

Alternative colour scheme. Not a pattern for fabrics, but one produced from a jpg of a stack of fabric items that was posted on Pixabay. The tile that this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i.

Source Firkin

 More Textures
Black Mamba@2X #58
 Dark  CC BY-SA 3.0

The name alone is awesome, but so is this sweet dark pattern.

Source Federica Pelzel

Carbon Fiber v2@2X #106
 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

Prismatic Abstract Geometric Background 4 No Black@2X #443
 Dark  CC 0

Prismatic Abstract Geometric Background 4

Source GDJ

Fancy Deboss #177
 Fabric  CC BY-SA 3.0

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

Source Daniel Beaton

Prismatic Polka Dots Mark II No Background #530
 Noise  CC 0

Prismatic Polka Dots Mark II No Background

Source GDJ

Background pattern 227 (colour 2) #2313
 Blue  CC 0

A seamless background drawn in Paint.net and vectorised with Vector Magic. The starting point was a photograph of drinking straws from Pixabay.

Source Firkin

Light Aluminum@2X #305
 Wall  CC BY-SA 3.0

Used correctly, this could be nice. Used in a bad way, all hell will break loose.

Source Atle Mo

Prismatic Pointers Background #388
 Noise  CC 0

Prismatic Pointers Background

Source GDJ

Retro Circles Background 5 No Black@2X #427
 Noise  CC 0

Retro Circles Background 5 No Black

Source GDJ

Background pattern 214 (colour 3) #2375
 Green  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. Alternative colour scheme.

Source Firkin