From a drawing in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892.
Source Firkin
A set of paper filters. The base texture is generated the same way, only the compositing mode is varied.
Source Lazur URH
A seamless texture of an abstract wall colored in shades of light orange brown.
Source V. Hartikainen
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
Here's a camo print with more tan and less green, such as might be used in a desert scenario. This is tileable, so it can be used as a wallpaper or background.
Source Eady
Prismatic Hypnotic Pattern 2 No Background
Source GDJ
A comeback for you: the popular Escheresque, now in black.
Source Patten
Might not be super subtle, but quite original in its form.
Source Alex Smith
Uses spirals from Pixabay. To get the basic tile select the rectangle in Inkscape and use shift+alt+i
Source Firkin
A pattern derived from repeating unit cells each derived from part of a fractal rendering in paint.net.
Source Firkin
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
From a drawing in 'At home', J. Sowerby, J. Crane and T. Frederick, 1881.
Source Firkin
Almost like little fish shells, or dragon skin.
Source Graphiste
The image is a remix of "edo pattern-samekomon".I changed the color of dots from black to white and added BG in light-brown.
Source Yamachem
Prismatic Abstract Geometric Background 4 No Black
Source GDJ
From a drawing in 'Cassell's Library of English Literature', Henry Morley, 1883.
Source Firkin
A seamless design of flowers remixed from a jpg on Pixabay by Prawny.
Source Firkin
From a drawing in 'In an Enchanted Island', William Mallock, 1892.
Source Firkin
This was formed by distorting an image of a background on Pixabay.
Source Firkin
From a design in 'Storia del Palazzo Vecchio in Firenze', Aurelio Gotti, 1889.
Source Firkin
Bigger is better, right? So here you have some large carbon fiber.
Source Factorio.us Collective
Greyscale version of a pattern that came out of playing with the 'slinky' plug-in for Paint.net
Source Firkin