Horizontal and vertical lines on a light gray background.
Source Adam Anlauf
A seamless pattern from a tile drawn in Paint.net and vectorised in Vector Magic
Source Firkin
A seamless pattern formed from background pattern 102
Source Firkin
The unit cell for this seamless pattern can be had in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin
Because I love dark patterns, here is Brushed Alum in a dark coating.
Source Tim Ward
The name alone is awesome, but so is this sweet dark pattern.
Source Federica Pelzel
Square design drawn in Paint.net and vectorized in Vector Magic.
Source Firkin
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
A seamless dark leather-like background texture with diagonal lines that look like stitches.
Source V. Hartikainen
Vector version of a png that was uploaded to Pixabay by pencilparker
Source Firkin
Remixed from a drawing that was uploaded to Pixabay by DavidZydd
Source Firkin
Seamless pattern made from a tile that can be obtained in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin
Have you wondered about how it feels to be buried alive? Here is the pattern for it.
Source Hendrik Lammers
Remixed from a drawing in 'Hungary. A guide book. By several authors', 1890.
Source Firkin
A seamlessly repeating background pattern of wood. The image is procedurally generated, and, I think, it's turned out quite well.
Source V. Hartikainen
Bright gray tones with a hint of some metal surface.
Source Hendrik Lammers
Remixed from a drawing in 'Chambéry à la fin du XIVe siècle', Timoleon Chapperon, 1863.
Source Firkin
After 1 comes 2, same but different. You get the idea.
Source Hendrik Lammers
A free seamless background with pink spots.
Source V. Hartikainen
Sharp but soft triangles in light shades of gray.
Source Pixeden