This background pattern contains a seamless texture of bark. It's not very realistic, but I think it looks quite nice.
Source V. Hartikainen
Prismatic Abstract Line Art Pattern Background
Source GDJ
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
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
Oh yes, it happened! A pattern in full color.
Source Atle Mo
The image is a seamless pattern of a fishnet.
Source Yamachem
Derived from an image that was uploaded to Pixabay by Darkmoon1968
Source Firkin
Simple gray checkered lines, in light tones.
Source Radosław Rzepecki
The tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
A seamless background colored in pale orange. It has a paper like texture with diagonal grid pattern.
Source V. Hartikainen
From a drawing in 'A Guide to the Guildhall of the City of London', John Baddeley, 1898.
Source Firkin
I guess this one is inspired by an office. A dark office.
Source Andrés Rigo.
Made by distorting a simple pattern using the 'sin waves' plugin for Paint.net and vectorising in Vector Magic
Source Firkin
Zero CC tileable bark texture, photographed and made by me. CC0
Source Sojan Janso
From an image on opengameart.org shared by rubberduck.
Source Firkin
Black brick wall pattern. Brick your site up!
Source Alex Parker
Tiny, tiny 3D cubes. Reminds me of the good old pattern from k10k.
Source Etienne Rallion
Drawn in Paint.net and vectorised in Vector Magic.
Source Firkin
A simple example on using clones. You can generate a nice base for a pattern fill quickly with it.
Source Lazur URH
A bit strange this one, but nice at the same time.
Source Diogo Silva
Remixed from a drawing that was uploaded to Pixabay by DavidZydd
Source Firkin
Lovely pattern with some good-looking non-random noise lines.
Source Zucx
Prismatic Abstract Geometric Background 4
Source GDJ