This was formed by distorting an image of a background on Pixabay.
Source Firkin
A seamless web background with texture of aged grid paper.
Source V. Hartikainen
Sharp but soft triangles in light shades of gray.
Source Pixeden
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
CC0 remixed from a drawing. Walter Crane, 1914, Firkin.
Source SliverKnight
Used correctly, this could be nice. Used in a bad way, all hell will break loose.
Source Atle Mo
A simple example on using clones. You can generate a nice base for a pattern fill quickly with it.
Source Lazur URH
A seamless paper background colored in pale yellow.
Source V. Hartikainen
A pattern derived from repeating unit cells each derived from part of a fractal rendering in paint.net.
Source Firkin
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
From a design found in 'History of the Virginia Company of London; with letters to and from the first Colony, never before printed', Edward Neill, 1869.
Source Firkin