From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Abstract Geometric Monochrome Pattern Prismatic No Background
Source GDJ
Colorful Floral Background 3 No Black
Source GDJ
Black brick wall pattern. Brick your site up!
Source Alex Parker
Fix side and a seamless pattern formed from circles.
Source SliverKnight
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Dark squares with some virus-looking dots in the grid.
Source Hugo Loning
A seamless texture of black leather. I think it will look best when used in headers, footers or sidebars.
Source V. Hartikainen
A dark one with geometric shapes and dotted lines.
Source Mohawk Studios
Geometric triangles seem to be quite hot these days.
Source Pixeden
This one is super crisp at 2X. Lined paper with some dust and scratches.
Source HQvectors
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
This is a remix of "blue wave-seigaiha".I hope this subtle color version of Seigaiha would be suitable for background .
Source Yamachem
Seamless pattern formed from a square tile that can be retrieved in Inkscape by selecting the rectangle and using shift-alt-i.
Source Firkin
Psychedelic Geometric Background No Black
Source GDJ
From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
With a name like this, it has to be hot. Diagonal lines in light shades.
Source Isaac
A pattern formed from a squared tile. The tile can be accessed in Inkscape by selecting the rectangle and using shift-alt-i.
Source Firkin
Remixed from a drawing in 'Line and form', Walter Crane, 1914.
Source Firkin