Bigger is better, right? So here you have some large carbon fiber.
Source Factorio.us Collective
The following repeating website background is colored in a blue gray color and resembles a concrete wall or something similar to it.
Source V. Hartikainen
Prismatic Groovy Concentric Background 2 No Black
Source GDJ
A topographic map like this has actually been requested a few times, so here you go!
Source Sam Feyaerts
A dark one with geometric shapes and dotted lines.
Source Mohawk Studios
You could get a bit dizzy from this one, but it might come in handy.
Source Dertig Media
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
Black And White Floral Pattern Background Inverse
Source GDJ
Love the style on this one, very fresh. Diagonal diamond pattern. Get it?
Source INS
Based on several public domain drawings on Wikimedia Commons. This was formed from a rectangular tile. The tile can be accessed in Inkscape by selecting the rectangle and using shift-alt-i.
Source Firkin
One can never have too few rice paper patterns, so here is one more.
Source Atle Mo
An attempt for cleaning up the original image in a few steps.
Source Lazur URH
This could be a hippy vintage wallpaper.
Source Tileable Patterns
Remixed from a drawing in 'Hungary. A guide book. By several authors', 1890.
Source Firkin
From a drawing in 'In an Enchanted Island', William Mallock, 1892.
Source Firkin
An abstract web texture of a polished blue stone (or does it look more like ice).
Source V. Hartikainen
Sounds like something from World of Warcraft. Has to be good.
Source Tony Kinard
A seamless pattern the unit cell for which can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Prepared mostly as a raster in Paint.net and vectorised.
Source Firkin
A very dark spotted twinkle pattern for your twinkle needs.
Source Badhon Ebrahim
Mostly just mucked about with the colours and made one of the paths in the lead frame opaque. The glass remains transparent.
Source Firkin
From a drawing in 'Jardyne's Wife', Charles Wills, 1891.
Source Firkin