The unit cell for this seamless pattern can be had in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin
Vertical lines with a bumpy, yet crisp, feel to it.
Source Raasa
A mid-tone gray pattern with some cement looking texture.
Source Hendrik Lammers
Prismatic Geometric Pattern Background No Black
Source GDJ
From a drawing in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892.
Source Firkin
Prismatic Abstract Geometric Background 2 No Black
Source GDJ
Bigger is better, right? So here you have some large carbon fiber.
Source Factorio.us Collective
Snap! It’s a pattern, and it’s not grayscale! Of course you can always change the color in Photoshop.
Source Atle Mo
No relation to the band, but damn it’s subtle!
Source Thomas Myrman
This is the third pattern called Dark Denim, but hey, we all love them!
Source Brandon Jacoby
From drawing in 'Musings in Maoriland', Thomas Bracken, 1890.
Source Firkin
An orange vertically striped background pattern. Feel free to download and use this orange background pattern, for example, on the web). It resembles a wallpaper with vertical stripes or something similar to it.
Source V. Hartikainen
A seamless texture traced from an image on opengameart.org shared by Scouser.
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
More in the paper realm, this time with fibers.
Source Jorge Fuentes
Prismatic Curved Diamond Pattern 5 No Background
Source GDJ
Sort of like the back of a wooden board. Light, subtle, and stylish, just the way we like it!
Source Nikolalek
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
This background pattern contains a seamless texture of bark. It's not very realistic, but I think it looks quite nice.
Source V. Hartikainen
Prismatic Geometric Pattern Background
Source GDJ