To get the repeating unit, select the rectangle in Inkscape and use shift+alt+i
Source Firkin
Remixed from an image that was uploaded to Pixabay by CatherineClennan
Source Firkin
Prismatic Triangular Seamless Pattern III With Background
Source GDJ
Remixed from an image on Pixabay, the original having been uploaded by darkmoon1968.
Source Firkin
A version without colours blended together to give a different look.
Source Firkin
Here's a subtle marble-like background for use on websites.
Source V. Hartikainen
Prismatic Abstract Background Design
Source GDJ
A floral background formed from numerous clones of flower 117.
Source Firkin
Zero CC bark from fur tree tileable texture, photographed and made by me. CC0
Source Sojan Janso
Here is a new seamless wood texture for using as blog or website backgrounds.
Source V. Hartikainen
The classic notebook paper with horizontal stripes.
Source Are Sundnes
Prismatic Polka Dots Mark II 2 No Background
Source GDJ
The image is a seamless pattern of a fishnet.
Source Yamachem
This beige background pattern resembles a concrete wall with engravings or something similar to it.
Source V. Hartikainen
Inspired by this, I came up with this pattern. Madness!
Source Atle Mo
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin