From a drawing in 'Gately's World's Progress', Charles Beale, 1886.
Source Firkin
Dark wooden pattern, given the subtle treatment. based on texture from Cloaks.
A dark one with geometric shapes and dotted lines.
Source Mohawk Studios
Might not be super subtle, but quite original in its form.
Source Alex Smith
A seamless striped fabric-like texture colored in a dark reddish brown color.
Source V. Hartikainen
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
Prismatic Geometric Pattern Background
Source GDJ
With a name this awesome, how can I go wrong?
Source Nikolay Boltachev
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
Dare I call this a «flat pattern»? Probably not.
Source Dax Kieran
The starting point for this was drawn on the web site steamcoded.org/PolyskelionMaker.svg
Source Firkin
A seamless texture of an abstract wall colored in shades of light orange brown.
Source V. Hartikainen
A seamless gray background texture suitable for use on websites. To me, it has the look of stone. Feel free to modify it to meet your needs (by making it a bit lighter or darker, for example).
Source V. Hartikainen
A free background pattern with abstract green tiles.
Source V. Hartikainen
From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Drawn in Paint.net and vectorised in Vector Magic.
Source Firkin
A fun-looking elastoplast/band-aid pattern. A hint of orange tone in this one.
Source Josh Green
Light and tiny, just the way you like it.
Source Rohit Arun Rao
The unit cell for this seamless pattern can be had in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin