A smooth mid-tone gray, or low contrast if you will, linen pattern.
Source Jordan Pittman
Prismatic Hexagonalism Pattern No Background
Source GDJ
ZeroCC tileable beechwood wood texture, generated in Neo Texture Edit by me. CC0
Source Sojan Janso
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Fix side and a seamless pattern formed from circles.
Source SliverKnight
A pattern derived from part of a fractal rendering in Paint.net.
Source Firkin
Kaleidoscope Prismatic Abstract No Background
Source GDJ
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
Inspired by a 1930s wallpaper pattern I saw on TV.
Source Firkin
Background pattern originally a PNG drawn in Paint.net
Source Firkin
I love these crisp, tiny, super subtle patterns.
Source Badhon Ebrahim
Remixed from a design seen on Pixabay. The basic tile can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Prismatic Hypnotic Pattern No Background
Source GDJ
A browner version of the original weathered fence texture.
Source Firkin
This one is something special. I’d call it a flat pattern, too. Very well done, sir!
Source GetDiscount
Turn your site into a dragon with this great scale pattern.
Source Alex Parker
This background texture resembles stone. It may be used as a background on web pages or on some of their html elements (header, borders, menu bar, etc.). Just modify it for your needs.
Source V. Hartikainen