A car pattern?! Can it be subtle? I say yes!
Source Radosław Rzepecki
A seamless green background texture. The image is distributed under a Creative Commons License (like all of the images here).
Source V. Hartikainen
Colourful background achieved with gradient fills.
Source Firkin
A seamless pattern formed from a modified version of rwwgub's tile. To get the tile, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
From a drawing in 'Resa i Afrika, genom Angola, Ovampo och Damaraland', P. Moller, 1899.
Source Firkin
Black version of a pattern that came out of playing with the 'light rays' plug-in for Paint.net
Source Firkin
Bit of a strange name on this one, but still nice. Tiny gray square things.
Source Carlos Valdez
This reminds me of Game Cube. A nice light 3D cube pattern.
Source Sander Ottens
A pattern formed from a squared tile. The tile can be accessed in Inkscape by selecting the rectangle and using shift-alt-i.
Source Firkin
Super simple but very nice indeed. Gray with vertical stripes.
Source Merrin Macleod
A pattern formed from a squared tile. The tile can be accessed in Inkscape by selecting the rectangle and using shift-alt-i.
Source Firkin
Submitted in a cream color, but you know how I like it.
Source Devin Holmes
The following orange background pattern resembles a honeycomb.
Source V. Hartikainen
Number five from the same submitter, makes my job easy.
Source Dima Shiper
A seamless pattern the starting point for which was a 'rainbow twist' texture in Paint.net.
Source Firkin
Don’t look at this one too long if you’re high on something.
Source Luuk van Baars
This background has abstract texture with some similarities to wood.
Source V. Hartikainen
Prismatic Curved Diamond Pattern 5 No Background
Source GDJ
A grid of squares with green colours. Since the colours are randomly distributed it is automatically seamless.
Source Firkin
Derived from an image that was uploaded to Pixabay by darkmoon1968
Source Firkin
A colourful background drawn originally in paint.net and vectorised in Vector Magic.
Source Firkin
From a drawing in 'Picturesque New Guinea', J Lindt, 1887.
Source Firkin
The tile can be had by using shift+alt+i on the selected rectangle in Inkscape
Source Firkin