Here's a camo print with more tan and less green, such as might be used in a desert scenario. This is tileable, so it can be used as a wallpaper or background.
Source Eady
A dark brown fabric-like background texture with seamless pattern of winding stripes.
Source V. Hartikainen
You can never get enough of these tiny pixel patterns with sharp lines.
Source Designova
The rectangular tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
Honestly, who does not like a little pipe and mustache?
Source Luca Errico
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
Based on several public domain drawings on Wikimedia Commons. This was formed from a rectangular tile. The tile can be accessed in Inkscape by selecting the rectangle and using shift-alt-i
Source Firkin
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
The image depicts a seamless pattern of pine tree leaves.
Source Yamachem
A simple circle. That’s all it takes. This one is even transparent, for those who like that.
Source Saqib
This light blue background pattern is quite pleasing to the eye, it consists of a tiny rough grid pattern, which is seamless by design. That's it, if you like the color, you can use this seamless pattern in a web design without making any further modifications to it.
Source V. Hartikainen
From a drawing in 'Friend or Fortune? The story of a strange year', Robert Overton, 1897.
Source Firkin
Light gray paper pattern with small traces of fiber and some dust.
Source Atle Mo
And some more testing, this time with Seamless Studio. It’s Robots FFS!
Source Seamless Studio
Remixed from a design found in 'History of the Virginia Company of London; with letters to and from the first Colony, never before printed', Edward Neill, 1869.
Source Firkin
Mostly just mucked about with the colours and made one of the paths in the lead frame opaque. The glass remains transparent.
Source Firkin
A seamless pattern formed from a square tile. The tile can be retrieved by selecting the rectangle in Inkscape and using shift-alt-I.
Source Firkin
Inspired by a 1930s wallpaper pattern I saw on TV.
Source Firkin
Luxury pattern, looking like it came right out of Paris.
Source Daniel Beaton
Did anyone say The Hoff? This pattern is in no way related to Baywatch.
Source Josh Green
The first pattern on here using opacity. Try it on a site with a colored background, or even using mixed colors.
Source Nathan Spady