Could remind you a bit of those squares in Super Mario Bros, yeh?
Source Jeff Wall
Geometric triangles seem to be quite hot these days.
Source Pixeden
The first pattern on here using opacity. Try it on a site with a colored background, or even using mixed colors.
Source Nathan Spady
A topographic map like this has actually been requested a few times, so here you go!
Source Sam Feyaerts
Abstract Tiled Background Extended 10
Source GDJ
More Japanese-inspired patterns, Gold Scales this time.
Source Josh Green
This is a remix of "geometrical pattern 01".
Source Yamachem
No relation to the band, but damn it’s subtle!
Source Thomas Myrman
A playful triangle pattern with different shades of gray.
Source Dimitrie Hoekstra
Your eyes can trip a bit from looking at this – use it wisely.
Source Michal Chovanec
A bit like some carbon, or knitted netting if you will.
Source Anna Litvinuk
From a design found in 'History of the Virginia Company of London; with letters to and from the first Colony, never before printed', Edward Neill, 1869.
Source Firkin
Same classic 45-degree pattern, dark version.
Source Luke McDonald
It’s big, it’s gradient—and it’s square.
Source Brankic1979
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
A very dark asfalt pattern based off of a photo taken with my iPhone.
Source Atle Mo
Prismatic Rounded Squares Grid 4 No Background
Source GDJ
Submitted by DomainsInfo – wtf, right? But hey, a free pattern.
Source DomainsInfo
The green fibers pattern will work very well in grayscale as well.
Source Matteo Di Capua
A seamless pattern based on a rectangular tile that can be retrieved in Inkscape by selecting the rectangle and using shift-alt-i.
Source Firkin