Not strictly seamless in that opposite edges are not identical. But they do marry up to make an interesting pattern
Source Firkin
Background Wall, Art Abstract, white Well & CC0 texture.
Source Ractapopulous
Used the 6th circle pattern designed by Viscious-Speed to create a print that can be used for card making or scrapbooking. Save as a PDF file for the best printing option.
Source Lovinglf
A seamless pattern formed from miutopia mug remixes on a tablecloth.
Source Firkin
The unit cell for this seamless pattern can be had in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin
To get the tile this is based on select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
From a drawing in 'Friend or Fortune? The story of a strange year', Robert Overton, 1897.
Source Firkin
Dark squares with some virus-looking dots in the grid.
Source Hugo Loning
A slightly grainy paper pattern with small horizontal and vertical strokes.
Source Atle Mo
Formed from a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
From a design found in 'History of the Virginia Company of London; with letters to and from the first Colony, never before printed', Edward Neill, 1869.
Source Firkin
Subtle scratches on a light gray background.
Source Andrey Ovcharov
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
Tile-able Dark Brown Wood Background. Feel free to use it as a background image in your designs or somewhere on the web. By the way, the color seems to be close to Coffee Brown.
Source V. Hartikainen
Hexagonal dark 3D pattern. What more can you ask for?
Source Norbert Levajsics
Never out of fashion and so much hotter than the 45º everyone knows, here is a sweet 60º line pattern.
Source Atle Mo
Abstract Tiled Background Extended 8
Source GDJ
Remixed from a drawing in 'Jezebel's Daughter', Wilkie Collins 1880
Source Firkin
Remixed from a drawing in 'Canadian forest industries July-December', 1915
Source Firkin
Sweet and subtle white plaster with hints of noise and grunge.
Source Phil Maurer