Sometimes you just need the simplest thing.
Source Fabricio
Formed from a tile based on a drawing from 'Viaggi d'un artista nell'America Meridionale', Guido Boggiani, 1895.
Source Firkin
Here's a new paper-like background for free use on personal and commercial projects (this applies to all background patterns here).
Source V. Hartikainen
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 Groovy Concentric Background No Black
Source GDJ
Horizontal and vertical lines on a light gray background.
Source Adam Anlauf
Bigger is better, right? So here you have some large carbon fiber.
Source Factorio.us Collective
A dark gray, sandy pattern with small light dots, and some angled strokes.
Source Atle Mo
I took the liberty of using Dmitry’s pattern and made a version without perforation.
Source Atle Mo
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
Here is a new seamless wood texture for using as blog or website backgrounds.
Source V. Hartikainen
Prismatic 3D Isometric Tessellation Pattern 6
Source GDJ
Did some testing with Repper Pro tonight, and this gray mid-tone pattern came out.
Source Atle Mo
A white version of the very popular linen pattern.
Source Ant Ekşiler
Sweet and subtle white plaster with hints of noise and grunge.
Source Phil Maurer
Heavily remixed from a drawing in 'Barbara Leybourne; a story of eighty years ago', Sarah Hamer, 1889.
Source Firkin
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
From a drawing in 'A Rolling Stone. A tale of wrongs and revenge', John Hartley, 1878.
Source Firkin
From a drawing in 'From Snowdon to the Sea. Striking stories of North and South Wales', Marie Trevelyan, 1895.
Source Firkin
An emulated “transparent” background pattern, like that of all kinds of computer graphics software.
Source AdamStanislav
Prismatic Hypnotic Pattern No Background
Source GDJ