Light gray grunge wall with a nice texture overlay.
Source Adam Anlauf
Black brick wall pattern. Brick your site up!
Source Alex Parker
One more from Badhon, sharp horizontal lines making an embossed paper feeling.
Source Badhon Ebrahim
From a drawing in 'Line and form', Walter Crane, 1914.
Source Firkin
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
Formed from a tile based on a drawing from 'Viaggi d'un artista nell'America Meridionale', Guido Boggiani, 1895.
Source Firkin
Everyone needs some stardust. Sprinkle it on your next project.
Source Atle Mo
Derived from a PNG that was uploaded to Pixabay by nutkitten
Source Firkin
From a drawing in 'Cowdray: the history of a great English House', Julia Roundell, 1884.
Source Firkin
I know there is one here already, but this is sexy!
Source Gjermund Gustavsen
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
A background pattern with blue on white vertical stripes.
Source V. Hartikainen
From a drawing in 'Les Chroniqueurs de l'Histoire de France depuis les origines jusqu'au XVIe siècle', Henriette Witt, 1884.
Source Firkin
A very dark spotted twinkle pattern for your twinkle needs.
Source Badhon Ebrahim
Background Wall, Art Abstract, Block Well & CC0 texture.
Source Ractapopulous
From a drawing in 'In an Enchanted Island', William Mallock, 1892.
Source Firkin
Here's an yet another seamless note paper texture for use as a background on websites.
Source V. Hartikainen
Not a flat you live inside, like in the UK – but a flat piece of cardboard.
Source Appleshadow
8 by 8 pixels, and just what the title says.
Source pixilated
Inspired by a pattern seen on a public domain image of a very old tile. To get the unit cell, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin