A free seamless background image with a texture of dark red "canvas". It should look very nice on web sites.
Source V. Hartikainen
Abstract Tiled Background Extended 6
Source GDJ
This one has rusty dark brown texture.
Source V. Hartikainen
Light gray grunge wall with a nice texture overlay.
Source Adam Anlauf
Prismatic Groovy Concentric Background 3 No Black
Source GDJ
A seamless pattern from a tile made from a jpg on Pixabay. To get the tile select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
Remixed from a JPG that was uploaded to Pixabay by Osckar
Source Firkin
The file was named striped lens, but hey – Translucent Fibres works too.
Source Angelica
The tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
A seamless marble-like texture colored in light blue.
Source V. Hartikainen
Prismatic Groovy Concentric Background 2
Source GDJ
Remixed from an image that was uploaded to Pixabay by Pixeline
Source Firkin
A tile-able background for websites with paper-like texture and a grid pattern layered on top of it.
Source V. Hartikainen
A repeatable image with dark background and metal grid pattern.
Source V. Hartikainen
A dark metallic background with a pattern of stamped dots. Here's a dark "metallic" background pattern for you.
Source V. Hartikainen
Super subtle indeed, a medium gray pattern with tiny dots in a grid.
Source Designova
Zero CC Mossy stone tileable texture, photographed and made by me. CC0
Source Sojan Janso
Remixed from a drawing in 'Paul's Sister', Frances Peard, 1889.
Source Firkin
A dark one with geometric shapes and dotted lines.
Source Mohawk Studios
Prismatic Geometric Pattern Background No Black
Source GDJ