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
A free seamless background image with abstract texture of green "curtain".
Source V. Hartikainen
Some more diagonal lines and noise, because you know you want it.
Source Atle Mo
To get the tile this is based on select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Wild Oliva or Oliva Wilde? Darker than the others, sort of a medium dark pattern.
Source Badhon Ebrahim
This is the remix of "Strawberry Pattern Background" uploaded by "GDJ". Thanks. I realigned strawberries so as to get seamless and changed the BG color.
Source Yamachem
Dark and hard, just the way we like it. Embossed triangles makes a nice pattern.
Source Ivan Ginev
Geometric lines are always hot, and this pattern is no exception.
Source Listvetra
A seamless gray background texture suitable for use on websites. To me, it has the look of stone. Feel free to modify it to meet your needs (by making it a bit lighter or darker, for example).
Source V. Hartikainen
Background formed from the original with an emboss effect
Source GDJ
A set of paper filters. The base texture is generated the same way, only the compositing mode is varied.
Source Lazur URH
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
This is so subtle you need to bring your magnifier!
Source Carlos Valdez
A nice and simple white rotated tile pattern.
Source Another One
Don’t look at this one too long if you’re high on something.
Source Luuk van Baars
A dark metallic background with a pattern of stamped dots. Here's a dark "metallic" background pattern for you.
Source V. Hartikainen
Number 5 in a series of 5 beautiful patterns. Can be found in colors on the submitter’s website.
Source Janos Koos
Hexagonal dark 3D pattern. What more can you ask for?
Source Norbert Levajsics
As far as fabric patterns goes, this is quite crisp.
Source Heliodor Jalba
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett