This is indeed a bit strange, but here’s to the crazy ones!
Source Christopher Buecheler
Prismatic Abstract Geometric Background 4 No Black
Source GDJ
Utilising some flowers from Almeidah. To get the unit tile, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
A free grid paper background pattern for using on web sites.
Source V. Hartikainen
Coming in at 666x666px, this is an evil big pattern, but nice and soft at the same time.
Source Atle Mo
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
The image depicts a seamless pattern of a snow crystal.I referred to a book called ”sekka-zusetsu” or "雪華図説" which means an illustrated explanation about snow crystals.This book was published in 1832 (天保3年) or Edo period.For more about "雪華図説",see here:dl.ndl.go.jp/info:ndljp/pid/2536975
Source Yamachem
A background pattern inspired by designs seen in 'Burghley. The Life of William Cecil', William Charlton, 1857.
Source Firkin
A fun-looking elastoplast/band-aid pattern. A hint of orange tone in this one.
Source Josh Green
This one looks like a cork panel. Feel free to use it as a tiled background on your blog or website.
Source V. Hartikainen
From a drawing in 'Gately's World's Progress', Charles Beale, 1886.
Source Firkin
Very dark pattern with some noise and 45-degree lines.
Source Stefan Aleksić
On a large canvas you can see it tiling, but used on smaller areas, it’s beautiful.
Source Paul Phönixweiß
This one is amazing, truly original. Go use it!
Source Viahorizon
Prismatic Triangular Seamless Pattern III With Background
Source GDJ
One more sharp little tile for you. Subtle circles this time.
Source Blunia
Sometimes you just need the simplest thing.
Source Fabricio
From a drawing in 'The Quiver of Love', Walter Crane, 1876
Source Firkin
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
Submitted as a black pattern, I made it light and a few steps more subtle.
Source Andy