People seem to enjoy dark patterns, so here is one with some circles.
Source Atle Mo
Traced from a drawing in 'Household Stories from the Collection of the Brothers Grimm', Wilhelm Carl Grimm , 1882.
Source Firkin
Embossed lines and squares with subtle highlights.
Source Alex Parker
Bright Multicolored Floral Background by Karen Arnold from PDP.
Source GDJ
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Derived from a drawing in 'The Murmur of the Shells', Samuel Cowen, 1879.
Source Firkin
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
An alternative colour scheme to the original seamless pattern.
Source Firkin
You know you love wood patterns, so here’s one more.
Source Richard Tabor
Alternative colour scheme to the original.
Source Firkin
A monochrome pattern from a tile that can be had by selecting the rectangle in Inkscaope and using shift+alt+i
Source Firkin
Prismatic Curved Diamond Pattern No Background
Source GDJ
Looks a bit like concrete with subtle specks spread around the pattern.
Source Mladjan Antic
The tile can be had by selecting the rectangle in Inkscape and using shift+alt+i. Remixed from a drawing in 'Flowers of Song', Frederick Weatherly, 1895.
Source Firkin
Inspired by a pattern I saw in a 19th century book. This seamless pattern was created from a square tile. To get the tile, select the pattern in Inkscape and use shift+alt+i.
Source Firkin
A dark gray, sandy pattern with small light dots, and some angled strokes.
Source Atle Mo
Three shades of gray makes this pattern look like a small carbon fiber surface. Great readability even for small fonts.
Source Atle Mo
Drawn in Paint.net using the kaleidoscope plug-in and vectorised.
Source Firkin
Prismatic Abstract Geometric Background 2
Source GDJ
Fake or not, it’s quite luxurious.
Source Factorio.us Collective
A free green background pattern with a pattern of rhombuses on a seamless texture. Feel free to use it as a tiled background image on your web site.
Source V. Hartikainen