Inspired by a pattern I saw in a 19th century book. This seamless pattern was created from a square tile. To get the tile, select the pattern in Inkscape and use shift+alt+i.
Source Firkin
Another fairly simple design drawn in Paint.net and vectorized in Inkscape.
Source Firkin
Colour version of a pattern that came out of playing with the 'light rays' plug-in for Paint.net
Source Firkin
Prismatic Abstract Line Art Pattern Background
Source GDJ
This is a semi-dark pattern, sort of linen-y.
Source Sagive SEO
Colourful background achieved with gradient fills.
Source Firkin
Light gray paper pattern with small traces of fiber and some dust.
Source Atle Mo
From a drawing in 'Cowdray: the history of a great English House', Julia Roundell, 1884.
Source Firkin
A seamless striped fabric-like texture colored in a dark reddish brown color.
Source V. Hartikainen
From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
You know I’m a sucker for these. Well-crafted paper pattern.
Source Mihaela Hinayon
The Grid. A digital frontier. I tried to picture clusters of information as they traveled through the computer.
Source Haris Šumić
A seamless pattern from a tile drawn in Paint.net and vectorised in Vector Magic
Source Firkin
From a drawing in 'Artists and Arabs', Henry Blackburn, 1868
Source Firkin
This yellow background consists of a pattern of glossy gold buttons arranged in polka dot style on a seamless texture. Here's a pale yellow background pattern. Feel free to use it for your needs!
Source V. Hartikainen
Prismatic Geometric Pattern Variation 2 With Background
Source GDJ
A bit strange this one, but nice at the same time.
Source Diogo Silva
Prismatic Abstract Geometric Background 4
Source GDJ
Prismatic Abstract Geometric Background derived from an image on Pixabay.
Source GDJ
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
Classy golf-pants pattern, or crossed stripes if you will.
Source Will Monson
Small gradient crosses inside 45-degree boxes, or bigger crosses if you will.
Source Wassim
This was formed by distorting an image of a background on Pixabay.
Source Firkin