A hint of orange color, and some crossed and embossed lines.
Source Adam Anlauf
Recreated from a pattern found in 'Az Osztrák-Magyar Monarchia irásban és képben', 1882. To get the tile this is based on select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
This is the remix of "Colorful Floral Pattern Background 3" uploaded by "GDJ". Thanks.
Source Yamachem
Prismatic Geometric Tessellation Pattern 2 No Background
Source GDJ
Small dots with minor circles spread across to form a nice mosaic.
Source John Burks
Here's a dark background pattern that contains a steel grid pattern as a texture. Use it as a website background or for other purposes. It's free!
Source V. Hartikainen
Greyscale version of a pattern that came out of playing with the 'light rays' plug-in for Paint.net
Source Firkin
Dark squares with some virus-looking dots in the grid.
Source Hugo Loning
A series of 5 patterns. That’s what the P stands for, if you didn’t guess it.
Source Dima Shiper
I know there is one here already, but this is sexy!
Source Gjermund Gustavsen
Prismatic Groovy Concentric Background 4 No Black
Source GDJ
Derived from a corner decoration itself found as a jpg on Pixabay.
Source Firkin
One more from Badhon, sharp horizontal lines making an embossed paper feeling.
Source Badhon Ebrahim
A seamless pattern made from the gold Penrose triangle by GDJ and the two remixes
Source Firkin
A seamless pattern the unit cell for which can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
This one has rusty dark brown texture.
Source V. Hartikainen
Prismatic 3D Isometric Tessellation Pattern 6
Source GDJ
Drawn in Paint.net and vectorised in Vector Magic.
Source Firkin
Classic vertical lines, in all its subtlety.
Source Cody L
Bigger is better, right? So here you have some large carbon fiber.
Source Factorio.us Collective
A light gray wall or floor (you decide) of concrete.
Source Atle Mo
To get the tile this is formed from select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
A version without colours blended together to give a different look.
Source Firkin