This seamless background image should look nice on websites. It has a dark blue gray texture with vertical stripes, it tiles seamlessly and, like all of the background images here, it's free. So, if you like it, take it!
Source V. Hartikainen
Alternative colour scheme for the original floral pattern.
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
A pattern derived from part of a fractal rendering in Paint.net.
Source Firkin
A seamless pattern formed from background pattern 102
Source Firkin
A monochrome pattern from a tile that can be had by selecting the rectangle in Inkscaope and using shift+alt+i
Source Firkin
Design drawn in Paint.net, vectorised using Vector Magic and finished in Inkscape.
Source Firkin
Remixed from a PNG that was uploaded to Pixabay by gingertea
Source Firkin
Classic vertical lines, in all its subtlety.
Source Cody L
Prismatic Abstract Background Design
Source GDJ
Background Wall, Art Abstract, Blue Well & CC0 texture.
Source Ractapopulous
I asked Gjermund if he could make a pattern for us – result!
Source Gjermund Gustavsen
A bit like some carbon, or knitted netting if you will.
Source Anna Litvinuk
Square design drawn in Paint.net and vectorized in Vector Magic.
Source Firkin
Seamless tile drawn in Paint.net and vectorised in Vector Magic.
Source Firkin
High detail stone wall with minor cracks and specks.
Source Projecteightyfive
A seamless pattern formed from a square tile. The tile can be retrieved by selecting the rectangle in Inkscape and using shift-alt-I. A version of the original with random colors.
Source Firkin
A light brushed aluminum pattern for your pleasure.
Source Tim Ward
Actually, there's no clouds in it, but I think it looks quite nice.
Source V. Hartikainen
Bright gray tones with a hint of some metal surface.
Source Hendrik Lammers
From a drawing in 'Navigations de Alouys de Cademoste.-La Navigation du Capitaine Pierre Sintre', Alvise da ca da Mosto, 1895.
Source Firkin
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
Light square grid pattern, great for a “DIY projects” sort of website, maybe?
Source Rafael Almeida
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
Prismatic Groovy Concentric Background 5 No Black
Source GDJ