Here's a bluish gray striped background pattern for use on web sites.
Source V. Hartikainen
CC0 and a seamless pattern from a tile drawn in Paint.net .
Source SliverKnight
Looks like an old wall. I guess that’s it then?
Source Viahorizon
A seamless pattern the starting point for which was a 'light rays' rendering in Paint.net.
Source Firkin
Sometimes you just need the simplest thing.
Source Fabricio
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
Prismatic Rounded Squares Grid 4 No Background
Source GDJ
This beige background pattern resembles a concrete wall with engravings or something similar to it.
Source V. Hartikainen
Abstract Stars Geometric Pattern Prismatic No Background
Source GDJ
Three shades of gray makes this pattern look like a small carbon fiber surface. Great readability even for small fonts.
Source Atle Mo
Formed by distorting a JPG from PublicDomainPictures
Source Firkin
A slightly more textured pattern, medium gray. A bit like a potato sack?
Source Bilal Ketab
A very dark spotted twinkle pattern for your twinkle needs.
Source Badhon Ebrahim
An interesting dark spotted pattern at an angle.
Source Hendrik Lammers
Prismatic Curved Diamond Pattern 3 No Background
Source GDJ
Prismatic Curved Diamond Pattern 8 No Background
Source GDJ
White little knobs, coming in at 10x10px. Sweet!
Source Amos
Old China with a modern twist, take two.
Source Adam Charlts
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
Made by distorting a simple pattern using the 'sin waves' plugin for Paint.net and vectorising in Vector Magic
Source Firkin
I guess this one is inspired by an office. A dark office.
Source Andrés Rigo.