From an image on opengameart.org shared by rubberduck.
Source Firkin
Bigger is better, right? So here you have some large carbon fiber.
Source Factorio.us Collective
From a drawing in 'The Quiver of Love', Walter Crane, 1876
Source Firkin
A seamless green background texture. The image is distributed under a Creative Commons License (like all of the images here).
Source V. Hartikainen
Here's a quite bright pink background pattern for use on websites. It doesn't look like a real fur, but it definitely resembles one.
Source V. Hartikainen
A very slick dark rubber grip pattern, sort of like the grip on a camera.
Source Sinisha
Beautiful dark noise pattern with some dust and grunge.
Source Vincent Klaiber
Colored maple leaves scattered on a surface. This is tileable, so it can be used as a background or wallpaper.
Source Eady
Imagine you zoomed in 1000X on some fabric. But then it turned out to be a skeleton!
Source Angelica
Sharp diamond pattern. A small 24x18px tile.
Source Tom Neal
A seamless pattern formed from a tile that can be had in Inkscape by selecting the rectangle and using shift+alt+i. Derived from a design in 'Storia del Palazzo Vecchio in Firenze', Aurelio Gotti, 1889.
Source Firkin
Vector version of a png that was uploaded to Pixabay by pencilparker
Source Firkin
Zero CC tileable seed texture, edited by me to be seamless from a Pixabay image. CC0
Source Sojan Janso
Kaleidoscope Prismatic Abstract No Background
Source GDJ
More in the paper realm, this time with fibers.
Source Jorge Fuentes
Number 2 in a series of 5 beautiful patterns. Can be found in colors on the submitter’s website.
Source Janos Koos
You know I’m a sucker for these. Well-crafted paper pattern.
Source Mihaela Hinayon
Derived from an image that was uploaded to Pixabay by TheDigitalArtist
Source Firkin
From a drawing in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892.
Source Firkin
From a drawing in 'Artists and Arabs', Henry Blackburn, 1868
Source Firkin
CC0 and a seamless pattern from a tile drawn in Paint.net .
Source SliverKnight
One can never have too few rice paper patterns, so here is one more.
Source Atle Mo