Clean and crisp lines all over the place. Wrap it up with this one.
Source Dax Kieran
A comeback for you: the popular Escheresque, now in black.
Source Patten
Zero CC tileable brick texture, photographed and made by me. CC0
Source Sojan Janso
A light gray fabric pattern with faded vertical stripes.
Source V. Hartikainen
This is so subtle I hope you can see it! Tweak at will.
Source Alexandre Naud
I know there is one here already, but this is sexy!
Source Gjermund Gustavsen
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
This one needs to be used in small areas; you can see it repeat.
Source Luca
Prismatic Triangular Seamless Pattern III With Background
Source GDJ
Seamless pattern formed from a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
Seamless pattern formed from a tile that can be had by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
You can never get enough of these tiny pixel patterns with sharp lines.
Source Designova
ZeroCC tileable moss texture, photographed and made by me. CC0
Source Sojan Janso
Remixed from a drawing in 'A Child of the Age', Francis Adams, 1894.
Source Firkin
To get the tile this is formed from select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
ZeroCC tileable wood boards texture, photographed and made by me. CC0
Source Sojan Janso
A cute x, if you need that sort of thing.
Source Juan Scrocchi
The rectangular tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
Prismatic Geometric Tessellation Pattern 2 No Background
Source GDJ