From a drawing in 'Hyde Park from Domesday-Book to date', John Ashton, 1896.
Source Firkin
A pattern 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
A hint of orange color, and some crossed and embossed lines.
Source Adam Anlauf
Tiny circle waves, almost like the ocean.
Source Sagive
Prismatic Abstract Background Design
Source GDJ
A seamless pattern from a tile drawn in Paint.net and vectorised in Vector Magic
Source Firkin
Looks like a technical drawing board: small squares forming a nice grid.
Source We Are Pixel8
CC0 and a seamless pattern from a tile drawn in Paint.net .
Source SliverKnight
A version without colours blended together to give a different look.
Source Firkin
Nicely crafted paper pattern, although a bit on the large side (500x593px).
Source Blaq Annabiosis
Colourful background achieved with gradient fills.
Source Firkin
This is the remix of "Tileable Wave Pattern 2" uploaded by "Arvin61r58".Thanks.I added a wire-mesh fence seamless pattern as a lower layer.
Source Yamachem
This one takes you back to math class. Classic mathematic board underlay.
Source Josh Green
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
A seamless background pattern of dark brown wood planks.
Source V. Hartikainen
Love me some light mesh on a Monday. Sharp.
Source Wilmotte Bastien
A heavy dark gray base, some subtle noise and a 45-degree grid makes this look like a pattern with a tactile feel to it.
Source Atle Mo
A blue gray fabric-like texture for websites. An yet another fabric-like texture. It has subtle vertical and diagonal stripes to it.
Source V. Hartikainen
Based on several public domain drawings on Wikimedia Commons. This was formed from a rectangular tile. The tile can be accessed in Inkscape by selecting the rectangle and using shift-alt-i
Source Firkin
Hey, you never know when you’ll need a bird pattern, right?
Source Pete Fecteau
The Grid. A digital frontier. I tried to picture clusters of information as they traveled through the computer.
Source Haris Šumić
The image depicts a seamless pattern of Japanese Edo pattern called "kikkou-matsu" or "亀甲松" meaning " tortoiseshell-pinetree".The real pinetree is like this: https://jp.pinterest.com/pin/500744052301065077/
Source Yamachem
This is so subtle: We’re talking 1% opacity. Get your squint on!
Source Atle Mo
A background pattern with a look of rough fabric.
Source V. Hartikainen
Pattern formed from simple shapes. Black version.
Source Firkin