Some rectangles, a bit of dust and grunge, plus a hint of concrete.
Source Atle Mo
Seamless Prismatic Pythagorean Line Art Pattern No Background. A seamless pattern that includes the original tile (go to Objects / Pattern / Pattern To Objects in Inkscape's menu to extract it).
Source GDJ
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
A nice one indeed, but I have a feeling we have it already? If you spot a copy, let me know on Twitter.
Source Graphiste
Not sure if this is related to the Nami you get in Google image search, but hey, it’s nice!
Source Dertig Media
More leather, and this time it’s bigger! You know, in case you need that.
Source Elemis
ZeroCC tileabel stone granite texture, edited from pixabay. CC0
Source Sojan Janso
Dark pattern with some nice diagonal stitched lines crossing over.
Source Ashton
Light square grid pattern, great for a “DIY projects” sort of website, maybe?
Source Rafael Almeida
More Japanese-inspired patterns, Gold Scales this time.
Source Josh Green
A free seamless background image with abstract texture of green "curtain".
Source V. Hartikainen
Inspired by a pattern I saw in a 19th century book. This seamless pattern was created from a square tile. To get the tile, select the pattern in Inkscape and use shift+alt+i.
Source Firkin
Scanned some rice paper and tiled it up for you. Enjoy.
Source Atle Mo
Remixed from a design seen in 'Burghley. The Life of William Cecil', William Charlton, 1857. The tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
An alternative colour scheme to the original seamless pattern.
Source Firkin
Smooth Polaroid pattern with a light blue tint.
Source Daniel Beaton
Prismatic Basic Pattern 2 No Background
Source GDJ
Prismatic Abstract Geometric Background 2 No Black
Source GDJ
A repeatable image with dark background and metal grid pattern.
Source V. Hartikainen
Love the style on this one, very fresh. Diagonal diamond pattern. Get it?
Source INS
A rusty grunge background for websites. Feel free to use it in your site's theme.
Source V. Hartikainen
He influenced us all. “Don’t be sad because it’s over. Smile because it happened.”
Source Atle Mo
This is so subtle you need to bring your magnifier!
Source Carlos Valdez
Made by distorting a simple pattern using the 'sin waves' plugin for Paint.net and vectorising in Vector Magic
Source Firkin