The unit cell for this seamless pattern can be had in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin
If you want png files of thisu can download them here :
Source Viscious-Speed
From a drawing in 'Line and form', Walter Crane, 1914.
Source Firkin
A simple but elegant classic. Every collection needs one of these.
Source Christopher Burton
Prismatic Curved Diamond Pattern No Background
Source GDJ
Imagine you zoomed in 1000X on some fabric. But then it turned out to be a skeleton!
Source Angelica
A seamless pattern based on a rectangular tile that can be retrieved in Inkscape by selecting the rectangle and using shift-alt-i.
Source Firkin
Dare I call this a «flat pattern»? Probably not.
Source Dax Kieran
Heavy depth and shadows here, but might work well on some mobile apps.
Source Damian Rivas
Zero CC tileable hard cover red book, scanned and made by me. CC0
Source Sojan Janso
Bigger is better, right? So here you have some large carbon fiber.
Source Factorio.us Collective
A bit of scratched up grayness. Always good.
Source Dmitry
Background Wall, Art Abstract, Block Well & CC0 texture.
Source Ractapopulous
Made by distorting a simple pattern using the 'sin waves' plugin for Paint.net and vectorising in Vector Magic
Source Firkin
Drawn in Paint.net and vectorised in Vector Magic.
Source Firkin
That’s what it is, a dark dot. Or sort of carbon looking.
Source Tsvetelin Nikolov
If you want png files of this u can download them here : viscious-speed.deviantart.com/gallery/27635117
Source Viscious-Speed
Adapted heavily from a JPG that was uploaded to Pixabay by Viscious-Speed.
Source Firkin
A slightly more textured pattern, medium gray. A bit like a potato sack?
Source Bilal Ketab
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
Number five from the same submitter, makes my job easy.
Source Dima Shiper
A huge one at 800x600px. Made from a photo I took going home after work.
Source Atle Mo
A free seamless texture of reptile skin colored in a dark brown color. As always, you may use it as a repeated background image in your web design works, or for any other purposes.
Source V. Hartikainen