Here I have tried to create something that would look like maple wood. Not sure how well it's turned out, but at least it looks like wood.
Source V. Hartikainen
Prismatic Groovy Concentric Background 4
Source GDJ
A seamless gray background texture suitable for use on websites. To me, it has the look of stone. Feel free to modify it to meet your needs (by making it a bit lighter or darker, for example).
Source V. Hartikainen
A background pattern inspired by designs seen in 'Burghley. The Life of William Cecil', William Charlton, 1857.
Source Firkin
As far as fabric patterns goes, this is quite crisp.
Source Heliodor Jalba
To get the tile this is based on, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
Tiny, tiny 3D cubes. Reminds me of the good old pattern from k10k.
Source Etienne Rallion
Light square grid pattern, great for a “DIY projects” sort of website, maybe?
Source Rafael Almeida
Remixed from a drawing in 'Hungary. A guide book. By several authors', 1890.
Source Firkin
From a drawing in 'At home', J. Sowerby, J. Crane and T. Frederick, 1881.
Source Firkin
A bit strange this one, but nice at the same time.
Source Diogo Silva
A comeback for you: the popular Escheresque, now in black.
Source Patten
Just to prove my point, here is a slightly modified dark version.
Source Atle Mo
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
From a drawing in 'Hundert Jahre in Wort und Bild', S. Stefan, 1899.
Source Firkin
This is so subtle: We’re talking 1% opacity. Get your squint on!
Source Atle Mo
Don’t look at this one too long if you’re high on something.
Source Luuk van Baars
Classic vertical lines, in all its subtlety.
Source Cody L
You know I love paper patterns. Here is one from Stephen. Say thank you!
Source Stephen Gilbert
Prismatic Curved Diamond Pattern 8 No Background
Source GDJ
A bit strange this one, but nice at the same time.
Source Diogo Silva
Retro Circles Background 5 No Black
Source GDJ
We have some linen patterns here, but none that are stressed. Until now.
Source Jordan Pittman
Neat little photography icon pattern.
Source Hossam Elbialy