This was formed by distorting an image of a background on Pixabay.
Source Firkin
Background Wall, Art Abstract, Block Well & CC0 texture.
Source Ractapopulous
You know I love paper patterns. Here is one from Stephen. Say thank you!
Source Stephen Gilbert
Not strictly seamless in that opposite edges are not identical. But they do marry up to make an interesting pattern
Source Firkin
Simple combination of stripy squares with their negatively coloured counterparts
Source Firkin
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Abstract Tiled Background Extended 12
Source GDJ
CC0 and a seamless pattern from a tile drawn in Paint.net .
Source SliverKnight
A seamless background drawn in Paint.net and vectorised with Vector Magic. The starting point was a photograph of drinking straws from Pixabay.
Source Firkin
Inspired by a JPG that was uploaded to Pixabay by kokon_art
Source Firkin
The rectangular tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
This is a grid, only it’s noisy. You know. Reminds you of those printed grids you draw on.
Source Vectorpile
Submitted by DomainsInfo – wtf, right? But hey, a free pattern.
Source DomainsInfo
Design drawn in Paint.net, vectorised using Vector Magic and finished in Inkscape.
Source Firkin
The name alone is awesome, but so is this sweet dark pattern.
Source Federica Pelzel
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Prismatic Groovy Concentric Background 2
Source GDJ
Sounds French. Some 3D square diagonals, that’s all you need to know.
Source Graphiste
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
The classic 45-degree diagonal line pattern, done right.
Source Jorick van Hees
Prismatic Abstract Geometric Background 5
Source GDJ
This is a more minute version of "fishnet 01".The image depicts a seamless pattern of a fishnet with a plenty of fish.It may be a lucky charm for fishermen.
Source Yamachem