Detailed but still subtle and quite original. Lovely gray shades.
Source Kim Ruddock
Prismatic Abstract Geometric Background 2 No Black
Source GDJ
Formed by distorting a JPG from PublicDomainPictures
Source Firkin
Carbon fiber is never out of fashion, so here is one more style for you.
Source Alfred Lee
A mid-tone gray pattern with some cement looking texture.
Source Hendrik Lammers
A seamless pattern formed from a tile made from ornament 22. To get the tile, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Small dots with minor circles spread across to form a nice mosaic.
Source John Burks
Vector version of a png that was uploaded to Pixabay by pencilparker
Source Firkin
Remixed from a drawing in 'Chambéry à la fin du XIVe siècle', Timoleon Chapperon, 1863.
Source Firkin
Prismatic Chevrons Pattern 5 With Background
Source GDJ
Sharp diamond pattern. A small 24x18px tile.
Source Tom Neal
Crossing lines with a subtle emboss effect on a dark background.
Source Stefan Aleksić
So tiny, just 7 by 7 pixels – but still so sexy. Ah yes.
Source Dmitriy Prodchenko
A seamless pattern formed from cross 4. To get the original tile select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
From a drawing in 'Resa i Afrika, genom Angola, Ovampo och Damaraland', P. Moller, 1899.
Source Firkin
Vertical lines with a bumpy, yet crisp, feel to it.
Source Raasa
One more from Badhon, sharp horizontal lines making an embossed paper feeling.
Source Badhon Ebrahim
Retro Circles Background 8 No Black
Source GDJ
There are many carbon patterns, but this one is tiny.
Source Designova
A seamless pattern formed from a sports car on clker.com. To get the tile, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Light honeycomb pattern made up of the classic hexagon shape.
Source Federica Pelzel
Remixed from a design seen in 'Burghley. The Life of William Cecil', William Charlton, 1857. The tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
This is the remix of "Colorful Floral Pattern Background 3" uploaded by "GDJ". Thanks.
Source Yamachem
From a drawing in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892.
Source Firkin
Design drawn in Paint.net, vectorised using Vector Magic and finished in Inkscape.
Source Firkin
The green fibers pattern will work very well in grayscale as well.
Source Matteo Di Capua