A seamless background drawn in Paint.net and vectorised with Vector Magic. The starting point was a photograph of drinking straws from Pixabay.
Source Firkin
I skipped number 3, because it wasn’t all that great. Sorry.
Source Dima Shiper
It looks like a polished stone surface to me. Download it for free, as always.
Source V. Hartikainen
A subtle shadowed checkered pattern. Increase the lightness for even more subtle sexiness.
Source Josh Green
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
Based on several public domain drawings on Wikimedia Commons. This was formed from a rectangular tile. The tile can be accessed in Inkscape by selecting the rectangle and using shift-alt-i.
Source Firkin
A repeating background of beige (or is it more vanilla yellow) textured stripes. One more background with stripes.
Source V. Hartikainen
Dark, crisp and subtle. Tiny black lines on top of some noise.
Source Wilmotte Bastien
Medium gray pattern with small strokes to give a weave effect.
Source Catherine
All good things come in threes, so I give you the third in my little concrete wall series.
Source Atle Mo
Prismatic Geometric Pattern Background 2
Source GDJ
Prismatic Curved Diamond Pattern 7 No Background
Source GDJ
A seamless pattern recreated from an image on Pixabay. It is reminiscent of parquet flooring and is formed from a square tile, which can be recovered in Inkscape by selecting the ungrouped rectangle and using shift-alt-I together.
Source Firkin
Prismatic Chevrons Pattern 5 With Background
Source GDJ
Made by distorting a simple pattern using the 'sin waves' plugin for Paint.net and vectorising in Vector Magic
Source Firkin
A re-make of the Gradient Squares pattern.
Source Dimitar Karaytchev
Classic vertical lines, in all its subtlety.
Source Cody L
A mid-tone gray pattern with some cement looking texture.
Source Hendrik Lammers
A seamless pattern based on a rectangular tile that can be retrieved in Inkscape by selecting the rectangle and using shift-alt-i.
Source Firkin
Derived from a corner decoration itself found as a jpg on Pixabay.
Source Firkin
Like the name suggests, this background image consists of a pattern of dark bricks. It may be an option for you, if you are looking for something that looks like a brick wall for use as a background on web pages. It's not a masterpiece, but looks pretty nice when is tiled.
Source V. Hartikainen
Prismatic Geometric Tessellation Pattern 2 No Background
Source GDJ
The tile this is formed from can be retrieved in Inkscape by selecting the rectangle and using shift+alt+i
Source Firkin
Prismatic Abstract Background Design No Black
Source GDJ
An attempt for cleaning up the original image in a few steps.
Source Lazur URH
Formed from a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Here's a dark background pattern that contains a steel grid pattern as a texture. Use it as a website background or for other purposes. It's free!
Source V. Hartikainen