This one needs to be used in small areas; you can see it repeat.
Source Luca
A repeating background for websites with a texture of black groove stripes.
Source V. Hartikainen
This is a semi-dark pattern, sort of linen-y.
Source Sagive SEO
From a drawing in 'The Quiver of Love', Walter Crane, 1876
Source Firkin
Got some felt in my mailbox today, so I scanned it for you to use.
Source Atle Mo
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
Design drawn in Paint.net, vectorised using Vector Magic and finished in Inkscape.
Source Firkin
White circles connecting on a light gray background.
Source Mark Collins
From a drawing in 'Chambéry à la fin du XIVe siècle', Timoleon Chapperon, 1863.
Source Firkin
From a drawing in 'Cassell's Library of English Literature', Henry Morley, 1883.
Source Firkin
This metal background pattern resembles a metal plate with rivets. Solid rivets on a metal plate.
Source V. Hartikainen
A seamless pattern from a tile drawn in Paint.net and vectorised in Vector Magic
Source Firkin
The image depicts meshed silhouettes of various things.The original image is an OCAL clipart called "Enter FOSSASIA 2016 #IoT T-shirt Design Contest" uploaded by "openclipart".Thanks.
Source Yamachem
Tile available in Inkscape using shift-alt-i on the selected rectangle
Source Firkin
Hexagonal dark 3D pattern. What more can you ask for?
Source Norbert Levajsics
A beautiful dark wood pattern, superbly tiled.
Source Omar Alvarado
The image depicts a seamless pattern of a tortoise in tortoiseshell (hexagon).
Source Yamachem
Continuing the geometric trend, here is one more.
Source Mike Warner
Not strictly seamless in that opposite edges are not identical. But they do marry up to make an interesting pattern
Source Firkin
A seamless pattern from a tile made from a jpg on Pixabay. To get the tile select the rectangle in Inkscape and use shift-alt-i.
Source Firkin