Dark wooden pattern, given the subtle treatment. based on texture from Cloaks. https://cloaks.deviantart.com
Source Atle Mo
A grid of squares with green colours. Since the colours are randomly distributed it is automatically seamless.
Source Firkin
A seamless pattern recreated from an image on Pixabay. It is reminiscent of parquet flooring and is formed from a square tile, which can be recovered in Inkscape by selecting the ungrouped rectangle and using shift-alt-I together.
Source Firkin
I skipped number 3, because it wasn’t all that great. Sorry.
Source Dima Shiper
A seamless chequerboard pattern formed from a tile that can be had in Inkscape by selecting the rectangle and using shift+alt+i. Alternative colour scheme.
Source Firkin
A seamless striped fabric-like texture colored in a dark reddish brown color.
Source V. Hartikainen
This light background pattern has a texture of "frozen" surface with diagonal stripes. Here's an yet another addition to the collection of free website backgrounds.
Source V. Hartikainen
A large (588x375px) sand-colored pattern for your ever-growing collection. Shrink at will.
Source Alex Tapein
The basic shapes never get old. Simple triangle pattern.
Source Atle Mo
Wild Oliva or Oliva Wilde? Darker than the others, sort of a medium dark pattern.
Source Badhon Ebrahim
I took the liberty of using Dmitry’s pattern and made a version without perforation.
Source Atle Mo
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Seamless pattern the tile for which can be had by using shift-alt-I on the selected rectangle in Inkscape.
Source Firkin
A seamless green background texture. The image is distributed under a Creative Commons License (like all of the images here).
Source V. Hartikainen
Have you wondered about how it feels to be buried alive? Here is the pattern for it.
Source Hendrik Lammers
Not strictly seamless in that opposite edges are not identical. But they do marry up to make an interesting pattern
Source Firkin
A seamless pattern of dark bricks. Maybe it's not very realistic, but it looks good in my opinion.
Source V. Hartikainen
Prismatic Rounded Squares Grid 3 No Background
Source GDJ
Derived from an image that was uploaded to Pixabay by pugmom40
Source Firkin
A dark metallic background with a pattern of stamped dots. Here's a dark "metallic" background pattern for you.
Source V. Hartikainen
A very dark spotted twinkle pattern for your twinkle needs.
Source Badhon Ebrahim
A hint of orange color, and some crossed and embossed lines.
Source Adam Anlauf
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
A light background pattern with diagonal stripes. Here's a simple light striped background for you.
Source V. Hartikainen