Dare I call this a «flat pattern»? Probably not.
Source Dax Kieran
This is the remix of an OCAL clipart called "Art Nouveau ornament" uploaded by "microcosme".Thanks.This is a seamless pattern of an Art Nouveau ornament.
Source Yamachem
Derived from an image that was uploaded to Pixabay by Darkmoon1968
Source Firkin
A seamless pattern created from a square tile. To get the tile, select the pattern in Inkscape and use shift+alt+i.
Source Firkin
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Nicely crafted paper pattern, although a bit on the large side (500x593px).
Source Blaq Annabiosis
Drawn in Paint.net and vectorised in Vector Magic.
Source Firkin
Not the Rebel alliance, but a dark textured pattern.
Source Hendrik Lammers
Prismatic Floral Background No Black
Source GDJ
Prismatic Geometric Pattern Background
Source GDJ
Zero CC bark from fur tree tileable texture, photographed and made by me. CC0
Source Sojan Janso
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
It has waves, so make sure you don’t get sea sickness.
Source CoolPatterns
Zero CC tileable hard cover red book, scanned and made by me. CC0
Source Sojan Janso
If you want png files of this u can download them here : viscious-speed.deviantart.com/gallery/27635117
Source Viscious-Speed
Light gray grunge wall with a nice texture overlay.
Source Adam Anlauf
To get the tile this is made up from select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
A bit strange this one, but nice at the same time.
Source Diogo Silva
Remixed from a drawing in 'Line and form', Walter Crane, 1914.
Source Firkin
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
Light honeycomb pattern made up of the classic hexagon shape.
Source Federica Pelzel
A seamless pattern created from a square tile. To get the tile, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin