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
Background formed from the original with an emboss effect
Source GDJ
Number 5 in a series of 5 beautiful patterns. Can be found in colors on the submitter’s website.
Source Janos Koos
This is a grid, only it’s noisy. You know. Reminds you of those printed grids you draw on.
Source Vectorpile
As far as fabric patterns goes, this is quite crisp.
Source Heliodor Jalba
An abstract texture of water. It's not perfect, but will do. You may download if you like it.
Source V. Hartikainen
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
We have some linen patterns here, but none that are stressed. Until now.
Source Jordan Pittman
Light gray grunge wall with a nice texture overlay.
Source Adam Anlauf
Nicely crafted paper pattern, although a bit on the large side (500x593px).
Source Blaq Annabiosis
This is sort of fresh, but still feels a bit old school.
Source Martuchox
Background Wall, Art Abstract, Blue Well & CC0 texture.
Source Ractapopulous
From a drawing in 'Worsborough; its historical associations and rural attractions', Joseph Wilkinson, 1879.
Source Firkin
A seamless background drawn in Paint.net and vectorised with Vector Magic. The starting point was a photograph of drinking straws from Pixabay.
Source Firkin
I love the movie Pineapple Express, and I’m also liking this Pineapple right here.
Source Audee Mirza
Black And White Floral Pattern Background from PDP.
Source GDJ
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
A seamless pattern the unit cell for which can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
A seamless pattern formed from a tile made from ornament 22. To get the tile, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin