Nasty or not, it’s a nice pattern that tiles. Like they all do.
Source Badhon Ebrahim
The image depicts an edo-era pattern called "same-komon" or "鮫小紋"which looks like a shark skin.The "same" in Japanese means shark in English.
Source Yamachem
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
To get the tile this is made up from select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Prismatic Polyskelion Pattern No Background
Source GDJ
A grid of squares with green colours. Since the colours are randomly distributed it is automatically seamless.
Source Firkin
From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
I’m starting to think I have a concrete wall fetish.
Source Atle Mo
The name tells you it has curves. Oh yes, it does!
Source Peter Chon
Here's a seamless brown cork board background texture. Feel free to download or reshare if you like.
Source V. Hartikainen
A free seamless background image with a texture of dark red "canvas". It should look very nice on web sites.
Source V. Hartikainen
Continuing the geometric trend, here is one more.
Source Mike Warner
Light square grid pattern, great for a “DIY projects” sort of website, maybe?
Source Rafael Almeida
Submitted in a cream color, but you know how I like it.
Source Devin Holmes
It’s an egg, in the form of a pattern. This really is 2012.
Source Paul Phönixweiß
Derived from a corner decoration itself found as a jpg on Pixabay.
Source Firkin
Bright Multicolored Floral Background by Karen Arnold from PDP.
Source GDJ
Based on several public domain drawings on Wikimedia Commons. This was formed from a rectangular tile. The tile can be accessed in Inkscape by selecting the rectangle and using shift-alt-i.
Source Firkin
Used correctly, this could be nice. Used in a bad way, all hell will break loose.
Source Atle Mo
A seamless pattern formed from a tile that can be had in Inkscape by selecting the rectangle and using shift+alt+i. Derived from a design in 'Storia del Palazzo Vecchio in Firenze', Aurelio Gotti, 1889.
Source Firkin
The first pattern on here using opacity. Try it on a site with a colored background, or even using mixed colors.
Source Nathan Spady
Remixed from a drawing in 'Очерки Русской Исторіи въ памятникахъ быта', Petr Polevoi, 1879.
Source Firkin
A smooth mid-tone gray, or low contrast if you will, linen pattern.
Source Jordan Pittman