One of the few full-color patterns here, but this one was just too good to pass up.
Source Alexey Usoltsev
This seamless background image should look nice on websites. It has a dark blue gray texture with vertical stripes, it tiles seamlessly and, like all of the background images here, it's free. So, if you like it, take it!
Source V. Hartikainen
From a drawing in 'The Quiver of Love', Walter Crane, 1876
Source Firkin
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
Made by distorting a simple pattern using the 'sin waves' plugin for Paint.net and vectorising in Vector Magic
Source Firkin
ZeroCC tileable wood boards texture, photographed and made by me. CC0
Source Sojan Janso
A grid of squares with green colours. Since the colours are randomly distributed it is automatically seamless.
Source Firkin
Sounds like something from World of Warcraft. Has to be good.
Source Tony Kinard
To get the tile this is based on, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
It’s a hole, in a pattern. On your website. Dig it!
Source Josh Green
Vector version of a png that was uploaded to Pixabay by pencilparker
Source Firkin
I took the liberty of using Dmitry’s pattern and made a version without perforation.
Source Atle Mo
A seamless background pattern with impressed gray dots.
Source V. Hartikainen
Dark, crisp and subtle. Tiny black lines on top of some noise.
Source Wilmotte Bastien
Prismatic Geometric Tessellation Pattern 2 No Background
Source GDJ
Background Wall, Art Abstract, Blue Well & CC0 texture.
Source Ractapopulous
From a drawing in 'In an Enchanted Island', William Mallock, 1892.
Source Firkin
Inspired by a drawing in 'Kulturgeschichte', Freidrich Hellwald, 1896.
Source Firkin
You know I’m a sucker for these. Well-crafted paper pattern.
Source Mihaela Hinayon
Heavily remixed from a drawing that was uploaded to Pixabay by ractapopulous
Source Firkin
Dare I call this a «flat pattern»? Probably not.
Source Dax Kieran