People seem to enjoy dark patterns, so here is one with some circles.
Source Atle Mo
A criss-cross pattern similar to one I saw mown into a sports field.
Source Firkin
Love the style on this one, very fresh. Diagonal diamond pattern. Get it?
Source INS
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
I love the movie Pineapple Express, and I’m also liking this Pineapple right here.
Source Audee Mirza
Colour version of the original seamless pattern.
Source Firkin
This background has abstract texture with some similarities to wood.
Source V. Hartikainen
Formed by distorting a JPG from PublicDomainPictures
Source Firkin
Zero CC bark from fur tree tileable texture, photographed and made by me. CC0
Source Sojan Janso
Dark, crisp and subtle. Tiny black lines on top of some noise.
Source Wilmotte Bastien
A grid of squares with green colours. Since the colours are randomly distributed it is automatically seamless.
Source Firkin
Classic vertical lines, in all its subtlety.
Source Cody L
Detailed but still subtle and quite original. Lovely gray shades.
Source Kim Ruddock
So tiny, just 7 by 7 pixels – but still so sexy. Ah yes.
Source Dmitriy Prodchenko
From a drawing in 'Uit de geschiedenis der Heilige Stede te Amsterdam', Yohannes Sterck, 1898.
Source Firkin
Remixed from a drawing in 'Analecta Eboracensia', Thomas Widdrington, 1897.
Source Firkin
Inspired by the B&O Play, I had to make this pattern.
Source Atle Mo
Inspired by a 1930s wallpaper pattern I saw on TV.
Source Firkin
The image depicts a pattern of regular hexagon.As I made to use it for myself,I want to others to use it.Speaking about the ratio of the image, height : width = 2 : √3(1.732...)Ridiculous to say,I realized later that this image is not honey comb pattern.I have to slide the second row.
Source Yamachem
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 based on a tile that can be achieved by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
A seamless chequerboard pattern formed from a tile that can be had in Inkscape by selecting the rectangle and using shift+alt+i. Alternative colour scheme.
Source Firkin
A topographic map like this has actually been requested a few times, so here you go!
Source Sam Feyaerts