Might not be super subtle, but quite original in its form.
Source Alex Smith
A seamless pattern made from the gold Penrose triangle by GDJ and the two remixes
Source Firkin
A seamless pattern of "sewn stripes" colored in light gray.
Source V. Hartikainen
The tile this fill pattern is based on can be had by using shift+alt+i on the rectangle.
Source Firkin
Simple gray checkered lines, in light tones.
Source Radosław Rzepecki
An aged paper background tile with smeared and pressed text.
Source V. Hartikainen
A seamless pattern formed from a modified version of rwwgub's tile. To get the tile, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
A re-make of the Gradient Squares pattern.
Source Dimitar Karaytchev
Stefan is hard at work, this time with a funky pattern of squares.
Source Stefan Aleksić
It’s an egg, in the form of a pattern. This really is 2012.
Source Paul Phönixweiß
Prismatic Curved Diamond Pattern 6 No Background
Source GDJ
The tile this is based on can be retrieved by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Brushed aluminum, in a bright gray version. Lovely 2X as well.
Source Andre Schouten
And some more testing, this time with Seamless Studio. It’s Robots FFS!
Source Seamless Studio
Remixed from a drawing in 'Hungary. A guide book. By several authors', 1890.
Source Firkin
Actually, there's no clouds in it, but I think it looks quite nice.
Source V. Hartikainen
This was formed by distorting an image of a background on Pixabay.
Source Firkin
This is the remix of an Openclipart clipart called "Maze" uploaded by "any_ono_mous".Thanks.This is a seamless pattern of a maze.
Source Yamachem
Prismatic Abstract Geometric Background 4
Source GDJ
Bumps, highlight and shadows – all good things.
Source Badhon Ebrahim
The tile this is formed from can be retrieved in Inkscape by selecting the rectangle and using shift+alt+i
Source Firkin
Here's a bluish gray striped background pattern for use on web sites.
Source V. Hartikainen
Super simple but very nice indeed. Gray with vertical stripes.
Source Merrin Macleod
This is lovely, just the right amount of subtle noise, lines and textures.
Source Richard Tabor
f you want png files of this u can download them here : viscious-speed.deviantart.com/gallery/27635117
Source Viscious-Speed
Never out of fashion and so much hotter than the 45º everyone knows, here is a sweet 60º line pattern.
Source Atle Mo