Dark pattern with some nice diagonal stitched lines crossing over.
Source Ashton
Classic vertical lines, in all its subtlety.
Source Cody L
Just to prove my point, here is a slightly modified dark version.
Source Atle Mo
CC0 and a seamless pattern from a tile drawn in Paint.net .
Source SliverKnight
A background pattern inspired by designs seen in 'Burghley. The Life of William Cecil', William Charlton, 1857.
Source Firkin
From a drawing in 'Less Black than we're painted', James Payn, 1884.
Source Firkin
Prismatic Geometric Tessellation Pattern No Background
Source GDJ
The base gradient edited so now more details are rendered.
Source Lazur URH
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
A monochrome pattern from a tile that can be had by selecting the rectangle in Inkscaope and using shift+alt+i
Source Firkin
Prismatic Polka Dots Mark II No Background
Source GDJ
I’m starting to think I have a concrete wall fetish.
Source Atle Mo
The tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
As far as fabric patterns goes, this is quite crisp.
Source Heliodor Jalba
A black tile-able background with paper-like texture.
Source V. Hartikainen
A dark one with geometric shapes and dotted lines.
Source Mohawk Studios
Background pattern made in "Grunge-Like" style. Available in both SVG and JPG formats. Edit to your needs then click the download button.
Source V. Hartikainen
To get the tile this is based on, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
Prismatic Snowflakes Pattern 2 No Background
Source GDJ