Seamless pattern the tile for which can be had by using shift-alt-I on the selected rectangle in Inkscape.
Source Firkin
A grid of squares with green colours. Since the colours are randomly distributed it is automatically seamless.
Source Firkin
A seamless chequerboard pattern formed from a tile that can be had in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin
From a drawing in 'Les Chroniqueurs de l'Histoire de France depuis les origines jusqu'au XVIe siècle', Henriette Witt, 1884.
Source Firkin
Some more diagonal lines and noise, because you know you want it.
Source Atle Mo
Prismatic Abstract Geometric Background 4
Source GDJ
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Black brick wall pattern. Brick your site up!
Source Alex Parker
Prismatic Floral Background No Black
Source GDJ
You know you love wood patterns, so here’s one more.
Source Richard Tabor
This is the remix of an OCAL clipart called "Rain on Window" uploaded by "pagarmidna".Thanks.This is a seamless pattern of raindrops.
Source Yamachem
Prismatic Snowflakes Pattern 2 No Background
Source GDJ
To get the tile this is formed from select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
It’s an egg, in the form of a pattern. This really is 2012.
Source Paul Phönixweiß
A simple but elegant classic. Every collection needs one of these.
Source Christopher Burton
A pale olive green background with a seamless texture.
Source V. Hartikainen
ZeroCC tileable beechwood wood texture, generated in Neo Texture Edit by me. CC0
Source Sojan Janso
Used correctly, this could be nice. Used in a bad way, all hell will break loose.
Source Atle Mo
From a drawing in 'Artists and Arabs', Henry Blackburn, 1868
Source Firkin
Nice and simple crossed lines in dark gray tones.
Source Stefan Aleksić
Nicely executed tiling for an interesting pattern.
Source Ignasi Àvila Padró
I love the movie Pineapple Express, and I’m also liking this Pineapple right here.
Source Audee Mirza
A textured orange background pattern with vertical stripes.
Source V. Hartikainen
Square design drawn in Paint.net and vectorized in Vector Magic.
Source Firkin
It’s a hole, in a pattern. On your website. Dig it!
Source Josh Green
A seamless pattern formed from a sports car on clker.com. To get the tile, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin