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
Prismatic Geometric Tessellation Pattern 4 No Background
Source GDJ
The unit cell for this seamless pattern can be had in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin
If you want png files of this u can download them here : viscious-speed.deviantart.com/gallery/27635117
Source Viscious-Speed
From a drawing in 'Artists and Arabs', Henry Blackburn, 1868
Source Firkin
From a drawing in 'Resa i Afrika, genom Angola, Ovampo och Damaraland', P. Moller, 1899.
Source Firkin
A seamless pattern based on a square tile that can be retrieved in Inkscape by selecting the rectangle and using shift-alt-i.
Source Firkin
One more in the line of patterns inspired by Japanese/Asian styles. Smooth.
Source Kim Ruddock
This ons is quite old school looking. Retro, even. I like it.
Source Arno Declercq
A slightly grainy paper pattern with small horizontal and vertical strokes.
Source Atle Mo
Number 4 in a series of 5 beautiful patterns. Can be found in colors on the submitter’s website.
Source Janos Koos
As far as fabric patterns goes, this is quite crisp.
Source Heliodor Jalba
Formed by distorting an image on Pixabay that was uploaded by gustavorezende. 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
The tile this is based on can be retrieved by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
People seem to enjoy dark patterns, so here is one with some circles.
Source Atle Mo
Prismatic Abstract Geometric Background 4 No Black
Source GDJ
This is so subtle I hope you can see it! Tweak at will.
Source Alexandre Naud
Inspired by a 1930s wallpaper pattern I saw on TV.
Source Firkin
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
Alternative colour scheme for the original floral pattern.
Source Firkin
Remixed from a raster on Pixabay that was uploaded by ArtsyBee.
Source Firkin