From a drawing in 'The Quiver of Love', Walter Crane, 1876
Source Firkin
Not strictly seamless in that opposite edges are not identical. But they do marry up to make an interesting pattern
Source Firkin
A white version of the very popular linen pattern.
Source Ant Ekşiler
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Sharp diamond pattern. A small 24x18px tile.
Source Tom Neal
Remixed from a drawing in 'Hungary. A guide book. By several authors', 1890.
Source Firkin
CC0 and a seamless pattern from a tile drawn in Paint.net .
Source SliverKnight
Light gray paper pattern with small traces of fiber and some dust.
Source Atle Mo
I took the liberty of using Dmitry’s pattern and made a version without perforation.
Source Atle Mo
Recreated from a pattern found in 'Az Osztrák-Magyar Monarchia irásban és képben', 1882. To get the tile this is based on select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Colour version of the original seamless pattern.
Source Firkin
Same classic 45-degree pattern, dark version.
Source Luke McDonald
From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Prismatic Geometric Pattern Background
Source GDJ
Same as the black version, but now in shades of gray. Very subtle and fine grained.
Source Atle Mo
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
Prismatic Curved Diamond Pattern 3 No Background
Source GDJ
Carbon fiber is never out of fashion, so here is one more style for you.
Source Alfred Lee
More tactile goodness. This time in the form of some rough cloth.
Source Bartosz Kaszubowski
A seamless pattern from a tile drawn in Paint.net and vectorised in Vector Magic
Source Firkin
Pattern Background, Texture, Photoshop Structure style CC0 texture.
Source Darkmoon1968
A free repetitive background with a dark concrete wall like texture. This one may be used in dark web site designs.
Source V. Hartikainen