Bit of a strange name on this one, but still nice. Tiny gray square things.
Source Carlos Valdez
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
A grid of squares with green colours. Since the colours are randomly distributed it is automatically seamless.
Source Firkin
A light gray background pattern with seamless fabric-like texture and almost unnoticeable stripes.
Source V. Hartikainen
A seamless pattern formed from a square tile. The tile can be retrieved by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
Prismatic Chevrons Pattern 5 With Background
Source GDJ
A seamless pattern the unit cell for which can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
Looks a bit like concrete with subtle specks spread around the pattern.
Source Mladjan Antic
From a drawing in 'Real Sailor-Songs', John Ashton, 1891.
Source Firkin
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Here's a brown background pattern with subtle stripes. I hope you'll like the color. If not, feel free to change it using an image editor, if you know how of course. Personally, I'm using GIMP to create these backgrounds.
Source V. Hartikainen
Sharp diamond pattern. A small 24x18px tile.
Source Tom Neal
A new take on the black linen pattern. Softer this time.
Source Atle Mo
Continuing the geometric trend, here is one more.
Source Mike Warner
Derived from an image that was uploaded to Pixabay by pugmom40
Source Firkin
Prismatic Groovy Concentric Background
Source GDJ
A rusty grunge background for websites. Feel free to use it in your site's theme.
Source V. Hartikainen
Prismatic Abstract Background Design
Source GDJ
You could get a bit dizzy from this one, but it might come in handy.
Source Dertig Media
Inspired by this, I came up with this pattern. Madness!
Source Atle Mo
The tile this is based on was adapted from an image that was uploaded to Pixabay by frolicsomepl. It can be had in Inkscape by selecting the rectangle and using shift+alt+i
Source Firkin
You were craving more leather, so I whipped this up by scanning a leather jacket.
Source Atle Mo
CC0 and a seamless pattern from a tile drawn in Paint.net .
Source SliverKnight
Subtle scratches on a light gray background.
Source Andrey Ovcharov
A seamless background pattern with a texture of wood planks. This wood background pattern has vertically arranged planks. You may try to rotate it 90°, to see how it will look like when the wood planks are arranged horizontally.
Source V. Hartikainen