A browner version of the original weathered fence texture.
Source Firkin
Seamless Green Tile Background
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
This is the remix of an OCAL clipart called "Rain on Window" uploaded by "pagarmidna".Thanks.This is a seamless pattern of raindrops.
Source Yamachem
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
The tile this is based on can be retrieved by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Prismatic Abstract Geometric Background 5
Source GDJ
Derived from an image that was uploaded to Pixabay by mdmelo.
Source Firkin
Medium gray pattern with small strokes to give a weave effect.
Source Catherine
Like the name suggests, this background image consists of a pattern of dark bricks. It may be an option for you, if you are looking for something that looks like a brick wall for use as a background on web pages. It's not a masterpiece, but looks pretty nice when is tiled.
Source V. Hartikainen
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
Cubes as far as your eyes can see. You know, because they tile.
Source Jan Meeus
Remixed from a drawing in 'Works. Popular edition', John Ruskin, 1886.
Source Firkin
A pattern drawn in Paint.net and vectorized in Vector Magic.
Source Firkin
The name Paisley reminds me of an old British servant. That’s just me.
Source Swetha
Prismatic Groovy Concentric Background No Black
Source GDJ
A free tileable background colored in off-white (antique white) color.
Source V. Hartikainen
Paper pattern with small dust particles and 45-degree strokes.
Source Atle Mo
The first pattern on here using opacity. Try it on a site with a colored background, or even using mixed colors.
Source Nathan Spady