The first pattern on here using opacity. Try it on a site with a colored background, or even using mixed colors.
Source Nathan Spady
To get the tile this is based on select the rectangle in Inkscape and use shift+alt+i
Source Firkin
If you’re sick of the fancy 3D, grunge and noisy patterns, take a look at this flat 2D brick wall.
Source Listvetra
A textured blue background pattern with vertical stripes.
Source V. Hartikainen
A browner version of the original weathered fence texture.
Source Firkin
A seamless texture of black leather. I think it will look best when used in headers, footers or sidebars.
Source V. Hartikainen
You could get a bit dizzy from this one, but it might come in handy.
Source Dertig Media
Geometric triangles seem to be quite hot these days.
Source Pixeden
Can’t believe we don’t have this in the collection already! Slick woven pattern with crisp details.
Source Max Rudberg
A grid of squares with green colours. Since the colours are randomly distributed it is automatically seamless.
Source Firkin
Simple wide squares with a small indent. Fits all.
Source Petr Šulc.
Not sure if this is related to the Nami you get in Google image search, but hey, it’s nice!
Source Dertig Media
Snap! It’s a pattern, and it’s not grayscale! Of course you can always change the color in Photoshop.
Source Atle Mo
Prismatic Groovy Concentric Background 4
Source GDJ
From a drawing in 'Navigations de Alouys de Cademoste.-La Navigation du Capitaine Pierre Sintre', Alvise da ca da Mosto, 1895.
Source Firkin
If you want png files of this u can download them here : viscious-speed.deviantart.com/gallery/27635117
Source Viscious-Speed