Based on an image that was uploaded to Pixabay by devanath
Source Firkin
A free seamless texture of reptile skin colored in a dark brown color. As always, you may use it as a repeated background image in your web design works, or for any other purposes.
Source V. Hartikainen
A grid of squares with green colours. Since the colours are randomly distributed it is automatically seamless.
Source Firkin
Seamless pattern formed from a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
A dark one with geometric shapes and dotted lines.
Source Mohawk Studios
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
CC0 and a seamless pattern from a tile drawn in Paint.net .
Source SliverKnight
This is the third pattern called Dark Denim, but hey, we all love them!
Source Brandon Jacoby
This one takes you back to math class. Classic mathematic board underlay.
Source Josh Green