CC0 and a seamless pattern from a tile drawn in Paint.net .
Source SliverKnight
Same classic 45-degree pattern, dark version.
Source Luke McDonald
A seamless texture of black leather. I think it will look best when used in headers, footers or sidebars.
Source V. Hartikainen
A pattern derived from part of a fractal rendering in Paint.net.
Source Firkin
Colorful Floral Background 3 No Black
Source GDJ
Love me some light mesh on a Monday. Sharp.
Source Wilmotte Bastien
And some more testing, this time with Seamless Studio. It’s Robots FFS!
Source Seamless Studio
Remixed from a drawing in 'Maidenhood; or, the Verge of the Stream', Laura Jewry, 1876.
Source Firkin
The image is a remix of "edo pattern-samekomon".I changed the color of dots from black to white and added BG in light-yellow.
Source Yamachem
Zero CC tileable bark texture, photographed and made by me. CC0
Source Sojan Janso
Simple combination of stripy squares with their negatively coloured counterparts
Source Firkin
A pale yellow background pattern with vertical stripes. The stripes are partially faded. I think this background image turned out pretty well, especially those faded stripes.
Source V. Hartikainen
A seamless pattern formed from a square tile. The tile can be retrieved by selecting the rectangle in Inkscape and using shift-alt-I. Version with black background.
Source Firkin
Prismatic Chevrons Pattern 5 With Background
Source GDJ
CC0 remixed from a drawing. Walter Crane, 1914, Firkin.
Source SliverKnight
Remixed from a drawing in 'The Canadian horticulturist', 1892
Source Firkin
It looks very nice I think.
Source V. Hartikainen
You don’t see many mid-tone patterns here, but this one is nice.
Source Joel Klein
Colorful Floral Background 3 No Black
Source GDJ
Zero CC tileable ground cracked, crackled, texture, made by me.
Source Sojan Janso
Inspired by an image that was uploaded to Pixabay by geralt
Source Firkin
Small dots with minor circles spread across to form a nice mosaic.
Source John Burks
This makes me wanna shoot some pool! Sweet green pool table pattern.
Source Caveman