Colour version that is close to the original drawing uploaded to Pixabay by pencilparker.
Source Firkin
A repeating gloomy background image. This one consists of a pattern of black chains layered on top of a dark textured background.
Source V. Hartikainen
Made by distorting a simple pattern using the 'sin waves' plugin for Paint.net and vectorising in Vector Magic
Source Firkin
A seamless light gray paper texture with horizontal double lines.
Source V. Hartikainen
A free seamless background image with abstract texture of green "curtain".
Source V. Hartikainen
Prismatic Hexagonalism Pattern No Background
Source GDJ
Could be paper, could be a Polaroid frame – up to you!
Source Chaos
Bigger is better, right? So here you have some large carbon fiber.
Source Factorio.us Collective
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
A blue gray fabric-like texture for websites. An yet another fabric-like texture. It has subtle vertical and diagonal stripes to it.
Source V. Hartikainen
Fabric-ish patterns are close to my heart. French Stucco to the rescue.
Source Christopher Buecheler
Simple gray checkered lines, in light tones.
Source Radosław Rzepecki
Derived from an image that was uploaded to Pixabay by Darkmoon1968
Source Firkin
Seamless pattern formed from a tile that can be had by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin