Textured Red Brown Plastic, Free Background Pattern. Although there's already enough plastic in our lives, let's bring it to the web too.)
Source V. Hartikainen
A grid of squares with green colours. Since the colours are randomly distributed it is automatically seamless.
Source Firkin
To get the tile this is based on, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
This was formed by distorting an image of a background on Pixabay.
Source Firkin
A light background pattern with diagonal stripes. Here's a simple light striped background for you.
Source V. Hartikainen
Dark blue concrete wall with some small dust spots.
Source Atle Mo
Same as Silver Scales, but in black. Turn your site into a dragon with this great scale pattern.
Source Alex Parker
A seamless pattern formed from miutopia's cakes on a tablecloth.
Source Firkin
CC0 and a seamless pattern from a tile drawn in Paint.net .
Source SliverKnight
A large pattern with funky shapes and form. An original. Sort of origami-ish.
Source Luuk van Baars
No relation to the band, but damn it’s subtle!
Source Thomas Myrman
White fabric looking texture with some nice random wave features.
Source Hendrik Lammers
Horizontal and vertical lines on a light gray background.
Source Adam Anlauf
Prismatic Groovy Concentric Background No Black
Source GDJ
Abstract Ellipses Background Grayscale
Source GDJ
An emulated “transparent” background pattern, like that of all kinds of computer graphics software.
Source AdamStanislav
Abstract Tiled Background Extended 8
Source GDJ
Nasty or not, it’s a nice pattern that tiles. Like they all do.
Source Badhon Ebrahim
Cubes as far as your eyes can see. You know, because they tile.
Source Jan Meeus
I scanned a paper coffee cup. You know, in case you need it.
Source Atle Mo
Remixed from a drawing in 'Analecta Eboracensia', Thomas Widdrington, 1897.
Source Firkin
A seamless background texture of old cardboard.
Source V. Hartikainen