From a drawing in 'At home', J. Sowerby, J. Crane and T. Frederick, 1881.
Source Firkin
You can never get enough of these tiny pixel patterns with sharp lines.
Source Designova
Lovely light gray floral motif with some subtle shades.
Source GraphicsWall
Prismatic Curved Diamond Pattern 3 No Background
Source GDJ
To get the repeating unit, select the rectangle in Inkscape and use shift+alt+i
Source Firkin
This light background pattern has a texture of "frozen" surface with diagonal stripes. Here's an yet another addition to the collection of free website backgrounds.
Source V. Hartikainen
Small dots with minor circles spread across to form a nice mosaic.
Source John Burks
Medium gray fabric pattern with 45-degree lines going across.
Source Atle Mo
This one resembles a black concrete wall when is tiled. It should look great, at least with dark website themes.
Source V. Hartikainen
Dark, crisp and subtle. Tiny black lines on top of some noise.
Source Wilmotte Bastien
Seamless Light Background Texture.
Source V. Hartikainen
From a drawing in 'Artists and Arabs', Henry Blackburn, 1868.
Source Firkin
Formed from a tile based on a drawing from 'Viaggi d'un artista nell'America Meridionale', Guido Boggiani, 1895.
Source Firkin
Classic vertical lines, in all its subtlety.
Source Cody L
Turn your site into a dragon with this great scale pattern.
Source Alex Parker
A seamless background drawn in Paint.net and vectorised with Vector Magic. The starting point was a photograph of drinking straws from Pixabay.
Source Firkin
Adapted heavily from a JPG that was uploaded to Pixabay by Viscious-Speed.
Source Firkin
A seamless tessellation pattern. To get the tile this is formed from, select the pattern in Inkscape and use shift+alt+i.
Source Firkin
This was formed by distorting an image of a background on Pixabay.
Source Firkin
This one needs to be used in small areas; you can see it repeat.
Source Luca
CC0 and a seamless pattern from a tile drawn in Paint.net .
Source SliverKnight
This is a hot one. Small, sharp and unique.
Source GraphicsWall