A seamless pattern made from the gold Penrose triangle by GDJ and the two remixes
Source Firkin
A heavy dark gray base, some subtle noise and a 45-degree grid makes this look like a pattern with a tactile feel to it.
Source Atle Mo
Seamless pattern formed from a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
It almost looks a bit blurry, but then again, so are fishes.
Source Petr Šulc
Free tiled background with colorful stripes and white splatter.
Source V. Hartikainen
From a drawing in 'Storia del Palazzo Vecchio in Firenze', Aurelio Gotti, 1889.
Source Firkin
You can never get enough of these tiny pixel patterns with sharp lines.
Source Designova
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
A pattern formed from repeated instances of corner decoration 8. To get the basic tile select the rectangle in Inkscape and use shift+alt+i
Source Firkin
Love the style on this one, very fresh. Diagonal diamond pattern. Get it?
Source INS
Never out of fashion and so much hotter than the 45º everyone knows, here is a sweet 60º line pattern.
Source Atle Mo
Prismatic Floral Background No Black
Source GDJ
Dark, crisp and subtle. Tiny black lines on top of some noise.
Source Wilmotte Bastien
To get the tile this is based on select the rectangle in Inkscape and use shift-alt-i
Source Firkin
Nothing like a clean set of bed sheets, huh?
Source Badhon Ebrahim
White circles connecting on a light gray background.
Source Mark Collins
The first pattern on here using opacity. Try it on a site with a colored background, or even using mixed colors.
Source Nathan Spady
From a drawing in 'Hubert Montreuil, or the Huguenot and the Dragoon', Francisca Ouvry, 1873.
Source Firkin