A seamless pattern from a tile drawn in Paint.net and vectorised in Vector Magic
Source Firkin
Here's a tile-able wood background image for use in web design.
Source V. Hartikainen
The name alone is awesome, but so is this sweet dark pattern.
Source Federica Pelzel
Semi-light fabric pattern made out of random pixels in shades of gray.
Source Atle Mo
Prismatic Hexagonalist Pattern No Background
Source GDJ
Classic 45-degree pattern, light version.
Source Luke McDonald
This background pattern contains worn out colorful stripes as a texture.
Source V. Hartikainen
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Seamless pattern the tile for which can be had by using shift-alt-I on the selected rectangle in Inkscape.
Source Firkin
This background pattern contains a seamless texture of bark. It's not very realistic, but I think it looks quite nice.
Source V. Hartikainen
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
Prismatic Curved Diamond Pattern 4 No Background
Source GDJ
Prismatic Hexagonalism Pattern No Background
Source GDJ
The unit cell for this seamless pattern can be had in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin
From a drawing in 'Hubert Montreuil, or the Huguenot and the Dragoon', Francisca Ouvry, 1873.
Source Firkin
Sharp pixel pattern looking like some sort of fabric.
Source Dmitry
Number 5 in a series of 5 beautiful patterns. Can be found in colors on the submitter’s website.
Source Janos Koos
Alternative colour scheme. Not a pattern for fabrics, but one produced from a jpg of a stack of fabric items that was posted on Pixabay. The tile that this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
From a drawing in 'A Life Interest', Mrs Alexander, 1888.
Source Firkin