A seamless pattern formed from a sports car on clker.com. To get the tile, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Submitted as a black pattern, I made it light and a few steps more subtle.
Source Andy
Prismatic Groovy Concentric Background No Black
Source GDJ
Derived from an image that was uploaded to Pixabay by darkmoon1968
Source Firkin
The tile this is based on can be retrieved by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
A mid-tone gray pattern with some cement looking texture.
Source Hendrik Lammers
A seamless pattern formed from a tile that can be had in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin
Abstract Ellipses Background Grayscale
Source GDJ
More in the paper realm, this time with fibers.
Source Jorge Fuentes
Seamless pattern the tile for which can be had by using shift-alt-I on the selected rectangle in Inkscape.
Source Firkin
To get the tile this is formed from select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Dark squares with some virus-looking dots in the grid.
Source Hugo Loning
If you don’t like cream and pixels, you’re in the wrong place.
Source Mizanur Rahman
A seamless chequerboard pattern formed from a tile that can be had in Inkscape by selecting the rectangle and using shift+alt+i. Alternative colour scheme.
Source Firkin
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
Prismatic Abstract Geometric Background 2 No Black
Source GDJ
This was submitted in a beige color, hence the name. Now it’s a gray paper pattern.
Source Konstantin Ivanov
A seamless green background texture. The image is distributed under a Creative Commons License (like all of the images here).
Source V. Hartikainen
Heavy depth and shadows here, but might work well on some mobile apps.
Source Damian Rivas
One can never have too few rice paper patterns, so here is one more.
Source Atle Mo
From a drawing in 'At home', J. Sowerby, J. Crane and T. Frederick, 1881.
Source Firkin
Got some felt in my mailbox today, so I scanned it for you to use.
Source Atle Mo
One more from Badhon, sharp horizontal lines making an embossed paper feeling.
Source Badhon Ebrahim
A seamless pattern drawn originally in Paint.net by distorting a slice of background pattern 116 and copying the resulting triangle numerous times.
Source Firkin