There are quite a few grid patterns, but this one is a super tiny grid with some dust for good measure.
Source Dominik Kiss
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Submitted by DomainsInfo – wtf, right? But hey, a free pattern.
Source DomainsInfo
Prismatic Abstract Line Art Pattern Background 2
Source GDJ
A seamless pattern created from a square tile. To get the tile, select the pattern in Inkscape and use shift+alt+i.
Source Firkin
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
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
A seamless pattern formed from cross 4. To get the original tile select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
Seamless pattern the tile for which can be had by using shift-alt-I on the selected rectangle in Inkscape.
Source Firkin
Cubes as far as your eyes can see. You know, because they tile.
Source Jan Meeus
I guess this is inspired by the city of Ravenna in Italy and its stone walls.
Source Sentel
This background has abstract texture with some similarities to wood.
Source V. Hartikainen
A heavy hitter at 400x400px, but lovely still.
Source Breezi
Free tiled background with colorful stripes and white splatter.
Source V. Hartikainen
Inspired by a design found in 'Konstantinápolyi emlékeim', Miklos Chriszto, 1893.
Source Firkin
This was formed by distorting an image of a background on Pixabay.
Source Firkin
A free background tile with a pattern of pink bump dots. This background tile is sweet! Moreover, it's designed for use as website backgrounds.
Source V. Hartikainen
Prismatic Groovy Concentric Background 4 No Black
Source GDJ
This background pattern contains a texture of yellow wood planks. I think it looks quite original.
Source V. Hartikainen
A huge one at 800x600px. Made from a photo I took going home after work.
Source Atle Mo
Derived from an image that was uploaded to Pixabay by Kaz
Source Firkin