Super simple but very nice indeed. Gray with vertical stripes.
Source Merrin Macleod
Hexagonal dark 3D pattern. What more can you ask for?
Source Norbert Levajsics
Remixed from a drawing in 'A Child of the Age', Francis Adams, 1894.
Source Firkin
A seamless paper background colored in pale yellow.
Source V. Hartikainen
A car pattern?! Can it be subtle? I say yes!
Source Radosław Rzepecki
From a drawing in 'Resa i Afrika, genom Angola, Ovampo och Damaraland', P. Moller, 1899.
Source Firkin
Fabric-ish patterns are close to my heart. French Stucco to the rescue.
Source Christopher Buecheler
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
There are many carbon patterns, but this one is tiny.
Source Designova
CC0 and seamless wellington boot pattern.
Source SliverKnight
Remixed from a drawing in 'The Canadian horticulturist', 1892
Source Firkin
A topographic map like this has actually been requested a few times, so here you go!
Source Sam Feyaerts
I know there is one here already, but this is sexy!
Source Gjermund Gustavsen
Remixed from a drawing in 'Line and form', Walter Crane, 1914.
Source Firkin
I guess this is inspired by the city of Ravenna in Italy and its stone walls.
Source Sentel
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
A background pattern inspired by designs seen in 'Burghley. The Life of William Cecil', William Charlton, 1857.
Source Firkin
From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
The image depicts the Japanese Edo pattern called "seigaiha" or "青海波" meaning "blue -sea- wave".I hope it's suitable for the summer season.
Source Yamachem
From a drawing in 'Line and form', Walter Crane, 1914.
Source Firkin
A very dark asfalt pattern based off of a photo taken with my iPhone.
Source Atle Mo
A pattern formed from a photograph of a 16th century ceramic tile.
Source Firkin
Prismatic Rounded Squares Grid 4 No Background
Source GDJ
Subtle scratches on a light gray background.
Source Andrey Ovcharov