Classy golf-pants pattern, or crossed stripes if you will.
Source Will Monson
A dark one with geometric shapes and dotted lines.
Source Mohawk Studios
To get the tile this is formed from select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Cubes as far as your eyes can see. You know, because they tile.
Source Jan Meeus
Formed from decorative divider 184 in paint.net. Vectorised with Vector Magic.
Source Firkin
From a drawing in 'Hubert Montreuil, or the Huguenot and the Dragoon', Francisca Ouvry, 1873.
Source Firkin
From a drawing in 'Studies for Stories', Jean Ingelow, 1864.
Source Firkin
All good things come in threes, so I give you the third in my little concrete wall series.
Source Atle Mo
A bit simplified version. Although it could be edited out to be simpler. Anyway, this time the tiling is converted to a pattern fill -which is using clipping for the tile's edges.
Source Lazur URH
A free seamless background image with a texture of dark red "canvas". It should look very nice on web sites.
Source V. Hartikainen
From a drawing in 'Resa i Afrika, genom Angola, Ovampo och Damaraland', P. Moller, 1899.
Source Firkin
This was formed by distorting an image of a background on Pixabay.
Source Firkin
This background has abstract texture with some similarities to wood.
Source V. Hartikainen
Bumps, highlight and shadows – all good things.
Source Badhon Ebrahim
A seamless pattern formed from a square tile. The tile can be retrieved by selecting the rectangle in Inkscape and using shift-alt-I. A version of the original with random colors.
Source Firkin
The image depicts a seamless pattern of a tortoise in tortoiseshell (hexagon).
Source Yamachem
This background pattern contains a texture of yellow wood planks. I think it looks quite original.
Source V. Hartikainen
Design drawn in Paint.net, vectorised using Vector Magic and finished in Inkscape.
Source Firkin
I know there is one here already, but this is sexy!
Source Gjermund Gustavsen
Prismatic Curved Diamond Pattern No Background
Source GDJ
Sort of like the Photoshop transparent background, but better!
Source Alex Parker
Prismatic Triangular Background Design Mark II 5
Source GDJ