If you like it a bit trippy, this wave pattern might be for you.
Source Ian Soper
A dark one with geometric shapes and dotted lines.
Source Mohawk Studios
Zero CC tileable hard cover green book, scanned and made by me. CC0
Source Sojan Janso
This background pattern contains worn out colorful stripes as a texture.
Source V. Hartikainen
Formed from a tile based on a drawing from 'Viaggi d'un artista nell'America Meridionale', Guido Boggiani, 1895.
Source Firkin
Bigger is better, right? So here you have some large carbon fiber.
Source Factorio.us Collective
You may use it as is, or modify it as you like.
Source V. Hartikainen
Derived from elements found in a floral ornament drawing on Pixabay.
Source Firkin
Prismatic Groovy Concentric Background 3 No Black
Source GDJ
White handmade paper pattern with small bumps.
Source Marquis
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
Geometric lines are always hot, and this pattern is no exception.
Source Listvetra
A free background image with a seamless texture of cardboard. This texture of cardboard looks quite realistic, especially when is actually tiled.
Source V. Hartikainen
A comeback for you: the popular Escheresque, now in black.
Source Patten
Some more diagonal lines and noise, because you know you want it.
Source Atle Mo
A seamless web texture of "green stone".
Source V. Hartikainen
Textured Red Brown Plastic, Free Background Pattern. Although there's already enough plastic in our lives, let's bring it to the web too.)
Source V. Hartikainen
Inspired by a 1930s wallpaper pattern I saw on TV.
Source Firkin
In the spirit of WWDC 2011, here is a dark iOS inspired linen pattern.
Source Atle Mo
To get the tile this is based on, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
Vector version of a png that was uploaded to Pixabay by pencilparker
Source Firkin
From a drawing in 'Cowdray: the history of a great English House', Julia Roundell, 1884.
Source Firkin