This is a semi-dark pattern, sort of linen-y.
Source Sagive SEO
Derived from a drawing in 'The Murmur of the Shells', Samuel Cowen, 1879.
Source Firkin
A fun-looking elastoplast/band-aid pattern. A hint of orange tone in this one.
Source Josh Green
The square tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
Background Wall, Art Abstract, Block Well & CC0 texture.
Source Ractapopulous
Sort of reminds me of those old house wallpapers.
Source Tish
Tiny little fibers making a soft and sweet look.
Source Badhon Ebrahim
Paper model of a tetrahedron. Modelo de papel de um tetraedro.
Source laobc
The following orange background pattern resembles a honeycomb.
Source V. Hartikainen
Seamless pattern formed from a tile that can be extracted by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
This is the remix of "Strawberry Pattern Background" uploaded by "GDJ". Thanks. I realigned strawberries so as to get seamless and changed the BG color.
Source Yamachem
A dark one with geometric shapes and dotted lines.
Source Mohawk Studios
Background Wall, Art Abstract, Blue Well & CC0 texture.
Source Ractapopulous
A nice looking light gray background pattern with diagonal stripes.
Source V. Hartikainen
A seamless stone-like background for blogs or any other type of websites.
Source V. Hartikainen
Background formed from the original with an emboss effect
Source GDJ
A comeback for you: the popular Escheresque, now in black.
Source Patten
Like the name suggests, this background image consists of a pattern of dark bricks. It may be an option for you, if you are looking for something that looks like a brick wall for use as a background on web pages. It's not a masterpiece, but looks pretty nice when is tiled.
Source V. Hartikainen
Formed by distorting the inside front cover of 'Diversæ insectarum volatilium : icones ad vivum accuratissmè depictæ per celeberrimum pictorem', Jacob Hoefnagel, 1630.
Source Firkin
Made by distorting a simple pattern using the 'sin waves' plugin for Paint.net and vectorising in Vector Magic
Source Firkin
Medium gray fabric pattern with 45-degree lines going across.
Source Atle Mo
A repeating gloomy background image. This one consists of a pattern of black chains layered on top of a dark textured background.
Source V. Hartikainen
Remixed from a drawing in 'In an Enchanted Island', William Mallock, 1892.
Source Firkin
Prismatic Curved Diamond Pattern No Background
Source GDJ
Looks like an old wall. I guess that’s it then?
Source Viahorizon
A seamless texture of black leather. I think it will look best when used in headers, footers or sidebars.
Source V. Hartikainen
Prismatic Polka Dots 3 No Background
Source GDJ
Prismatic Abstract Line Art Pattern Background
Source GDJ