A seamless dark leather-like background texture with diagonal lines that look like stitches.
Source V. Hartikainen
Design drawn in Paint.net, vectorised using Vector Magic and finished in Inkscape.
Source Firkin
Seamless Green Tile Background
Source V. Hartikainen
If you want png files of this u can download them here : viscious-speed.deviantart.com/gallery/27635117
Source Viscious-Speed
This one is quite simple in design, it consists of vertical stripes layered on top of a seamless texture.
Source V. Hartikainen
The name tells you it has curves. Oh yes, it does!
Source Peter Chon
A seamless chequerboard pattern formed from a tile that can be had in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin
From a drawing in 'Line and form', Walter Crane, 1914.
Source Firkin
Recreated from a pattern found in 'Az Osztrák-Magyar Monarchia irásban és képben', 1882. To get the tile this is based on select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
A black tile-able background with paper-like texture.
Source V. Hartikainen
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
Not strictly seamless in that opposite edges are not identical. But they do marry up to make an interesting pattern
Source Firkin
Prismatic Rounded Squares Grid 3 No Background
Source GDJ
From a drawing in 'Line and form', Walter Crane, 1914.
Source Firkin
A simple but elegant classic. Every collection needs one of these.
Source Christopher Burton
A version without colours blended together to give a different look.
Source Firkin
Dark, square, clean and tidy. What more can you ask for?
Source Jaromír Kavan
From a drawing in 'Maidenhood; or, the Verge of the Stream', Laura Jewry, 1876.
Source Firkin
Prismatic Polka Dots Mark II 3 No Background
Source GDJ
A repeatable image with dark background and metal grid pattern.
Source V. Hartikainen