CC0 and a seamless pattern from a tile drawn in Paint.net .
Source SliverKnight
Black & white version of a pattern that came out of playing with the 'light rays' plug-in for Paint.net
Source Firkin
An abstract texture of black metal pipes (seamless).
Source V. Hartikainen
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
A free seamless background texture of "timber wall" (colored in dark brown).
Source V. Hartikainen
More bright luxury. This is a bit larger than fancy deboss, and with a bit more noise.
Source Viszt Péter
A seamless pattern based on a square tile that can be retrieved in Inkscape by selecting the rectangle and using shift-alt-i.
Source Firkin
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
To get the tile this is based on select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
A seamless pattern formed from background pattern 102
Source Firkin
A pattern derived from repeating unit cells each derived from part of a fractal rendering in paint.net.
Source Firkin
A seamless background colored in pale orange. It has a paper like texture with diagonal grid pattern.
Source V. Hartikainen
Prismatic Abstract Line Art Pattern Background
Source GDJ
This background pattern looks like bamboo to me. Feel free to download it for your website (for your blog perhaps?).
Source V. Hartikainen
A free seamless background texture that looks like a brown stone wall.
Source V. Hartikainen
The tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
Formed by heavily distorting part of a an image of a fish uploaded to Pixabay by GLady
Source Firkin
A grid of squares with green colours. Since the colours are randomly distributed it is automatically seamless.
Source Firkin
Small gradient crosses inside 45-degree boxes, or bigger crosses if you will.
Source Wassim
A light background pattern with diagonal stripes. Here's a simple light striped background for you.
Source V. Hartikainen
Scanned some rice paper and tiled it up for you. Enjoy.
Source Atle Mo