I know there is one here already, but this is sexy!
Source Gjermund Gustavsen
Same classic 45-degree pattern, dark version.
Source Luke McDonald
Remixed from a drawing in 'The March of Loyalty', Letitia MacClintock, 1884.
Source Firkin
Everyone loves a diamond, right? Make your site sparkle.
Source AJ Troxell
Nasty or not, it’s a nice pattern that tiles. Like they all do.
Source Badhon Ebrahim
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
White circles connecting on a light gray background.
Source Mark Collins
Seamless pattern formed from a tile that can be had by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
A classic dark tile for a bit of vintage darkness.
Source Listvetra
The tile this fill pattern is based on can be had by using shift+alt+i on the rectangle.
Source Firkin
Used in small doses, this could be a nice subtle pattern. Used on a large surface, it’s dirty!
Source Paul Reulat
Nicely crafted paper pattern, although a bit on the large side (500x593px).
Source Blaq Annabiosis
A set of paper filters. The base texture is generated the same way, only the compositing mode is varied.
Source Lazur URH
The tile for this is based on a repeating unit close to a design on Pixabay. It can be had by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
Not strictly seamless in that opposite edges are not identical. But they do marry up to make an interesting pattern
Source Firkin
Remixed from a raster on Pixabay, that was uploaded by ArtsyBee.
Source Firkin
Adapted heavily from a JPG that was uploaded to Pixabay by Viscious-Speed.
Source Firkin
Tweed is back in style – you heard it here first. Also, the @2X version here is great!
Source Simon Leo
A seamless pattern from a tile drawn in Paint.net and vectorised in Vector Magic
Source Firkin
A dark one with geometric shapes and dotted lines.
Source Mohawk Studios
A dark metallic background with a pattern of stamped dots. Here's a dark "metallic" background pattern for you.
Source V. Hartikainen
Psychedelic Geometric Background No Black
Source GDJ
Derived from elements found in a floral ornament drawing on Pixabay.
Source Firkin
Seamless Dark Grunge Texture. Here's a new grunge texture for use as a background.
Source V. Hartikainen