The first pattern on here using opacity. Try it on a site with a colored background, or even using mixed colors.
Source Nathan Spady
This is a semi-dark pattern, sort of linen-y.
Source Sagive SEO
Prismatic Groovy Concentric Background 2
Source GDJ
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
You know, tiny and sharp. I’m sure you’ll find a use for it.
Source Atle Mo
Abstract Geometric Monochrome Pattern Prismatic No Background
Source GDJ
Sort of reminds me of those old house wallpapers.
Source Tish
Background formed from the iconic plastic construction bricks that gave me endless hours of fun when I was a lad.
Source Firkin
Prismatic Abstract Geometric Background 2
Source GDJ
Inspired by a drawing in 'Kulturgeschichte', Freidrich Hellwald, 1896.
Source Firkin
Remixed from a design seen in 'Burghley. The Life of William Cecil', William Charlton, 1857.
Source Firkin
A gray background pattern with a texture of textile. Suits perfectly for web design.
Source V. Hartikainen
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
Prismatic Geometric Tessellation Pattern 2 No Background
Source GDJ
It almost looks a bit blurry, but then again, so are fishes.
Source Petr Šulc
The square tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
The image depicts a shell seamless pattern.I used an OCAL clipart called "Shell" uploaded by "jgm104".Thanks.
Source Yamachem
Small dots with minor circles spread across to form a nice mosaic.
Source John Burks
A pattern derived from repeating unit cells each derived from part of a fractal rendering in paint.net.
Source Firkin
Prismatic Groovy Concentric Background No Black
Source GDJ
From a drawing in 'Les Chroniqueurs de l'Histoire de France depuis les origines jusqu'au XVIe siècle', Henriette Witt, 1884.
Source Firkin
A monochrome pattern from a tile that can be had by selecting the rectangle in Inkscaope and using shift+alt+i
Source Firkin
Thin lines, noise and texture creates this crisp dark denim pattern.
Source Marco Slooten