A huge one at 800x600px. Made from a photo I took going home after work.
Source Atle Mo
Paper pattern with small dust particles and 45-degree strokes.
Source Atle Mo
A seamless pattern of dark bricks. Maybe it's not very realistic, but it looks good in my opinion.
Source V. Hartikainen
A pattern formed from a squared tile. The tile can be accessed in Inkscape by selecting the rectangle and using shift-alt-i.
Source Firkin
If you like it a bit trippy, this wave pattern might be for you.
Source Ian Soper
ZeroCC tileable wood boards texture, photographed and made by me. CC0
Source Sojan Janso
Square design drawn in Paint.net and vectorized in Vector Magic.
Source Firkin
The tile this fill pattern is based on can be had by using shift+alt+i on the rectangle.
Source Firkin
Remixed from a drawing in 'Hungary. A guide book. By several authors', 1890.
Source Firkin
From an image on opengameart.org shared by rubberduck.
Source Firkin
From a drawing in 'Cowdray: the history of a great English House', Julia Roundell, 1884.
Source Firkin
A seamless texture of a rough concrete surface.
Source V. Hartikainen
Remixed from a design seen on Pixabay. The basic tile can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
This texture looks like old leather. It should look great as a background on web pages.
Source V. Hartikainen
Just the symbols of the signs of the zodiac distributed in a chequer board-like pattern
Source Firkin
A hint of orange color, and some crossed and embossed lines.
Source Adam Anlauf
Could be paper, could be a Polaroid frame – up to you!
Source Chaos
Because I love dark patterns, here is Brushed Alum in a dark coating.
Source Tim Ward
Background Wall, Art Abstract, Block Well & CC0 texture.
Source Ractapopulous
This is so subtle I hope you can see it! Tweak at will.
Source Alexandre Naud
Zero CC tileable wood texture, made by me procedurally in Neo Texture Edit.
Source Sojan Janso
Background pattern made in "Grunge-Like" style. Available in both SVG and JPG formats. Edit to your needs then click the download button.
Source V. Hartikainen