Bigger is better, right? So here you have some large carbon fiber.
Source Factorio.us Collective
Background Wall, Art Abstract, Block Well & CC0 texture.
Source Ractapopulous
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
Inspired by an image that was uploaded to Pixabay by geralt
Source Firkin
Prismatic Polka Dots Mark II No Background
Source GDJ
The image depicts a seamless pattern of a snow crystal.I referred to a book called ”sekka-zusetsu” or "雪華図説" which means an illustrated explanation about snow crystals.This book was published in 1832 (天保3年) or Edo period.For more about "雪華図説",see here:dl.ndl.go.jp/info:ndljp/pid/2536975
Source Yamachem
Prismatic Abstract Geometric Background 4
Source GDJ
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Dark, square, clean and tidy. What more can you ask for?
Source Jaromír Kavan
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
Prismatic Geometric Pattern Background No Black
Source GDJ
A free seamless background image with abstract texture of green "curtain".
Source V. Hartikainen
Never out of fashion and so much hotter than the 45º everyone knows, here is a sweet 60º line pattern.
Source Atle Mo
A simple circle. That’s all it takes. This one is even transparent, for those who like that.
Source Saqib
Super simple but very nice indeed. Gray with vertical stripes.
Source Merrin Macleod
Alternative colour scheme for the original floral pattern.
Source Firkin
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
Geometric lines are always hot, and this pattern is no exception.
Source Listvetra
A car pattern?! Can it be subtle? I say yes!
Source Radosław Rzepecki
The texture of this background image has some similarities with leather, and it's colored in a dark brown color. So, if you are looking for a dark brown background image for your website, this may be an option for you.
Source V. Hartikainen