Got some felt in my mailbox today, so I scanned it for you to use.
Source Atle Mo
Simple combination of stripy squares with their negatively coloured counterparts
Source Firkin
To get the tile this is based on select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Not the Rebel alliance, but a dark textured pattern.
Source Hendrik Lammers
Dark, square, clean and tidy. What more can you ask for?
Source Jaromír Kavan
From a drawing in 'The Quiver of Love', Walter Crane, 1876
Source Firkin
This reminds me of Game Cube. A nice light 3D cube pattern.
Source Sander Ottens
This background image is great for using in web design or graphic design projects. And don't forget to visit the homepage. I frequently update this resource with fresh tileable backgrounds.
Source V. Hartikainen
A seamless pattern the starting point for which was a 'rainbow twist' texture in Paint.net.
Source Firkin
Prismatic Triangular Background Design Mark II 5
Source GDJ
A repeating background for websites with a texture of black groove stripes.
Source V. Hartikainen
Adapted heavily from a JPG that was uploaded to Pixabay by Viscious-Speed.
Source Firkin
From a drawing in 'Cowdray: the history of a great English House', Julia Roundell, 1884.
Source Firkin
Bigger is better, right? So here you have some large carbon fiber.
Source Factorio.us Collective
Prismatic Abstract Geometric Background 4 No Black
Source GDJ
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
Prismatic Curved Diamond Pattern 3 No Background
Source GDJ
From a drawing in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892.
Source Firkin
From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin