Dare I call this a «flat pattern»? Probably not.
Source Dax Kieran
Remixed from a drawing in 'A Child of the Age', Francis Adams, 1894.
Source Firkin
This is a remix of "flower seamless pattern".I rotated the original image by 90 degrees.This is a seamless pattern of flowers.These horizontal wavy lines are one of Edo patterns which is called "tatewaku or tachiwaku or 立湧" that represents uprising steam or vapor.
Source Yamachem
Prismatic Isometric Cube Extra Pattern No Background
Source GDJ
Not strictly seamless in that opposite edges are not identical. But they do marry up to make an interesting pattern
Source Firkin
It looks very nice I think.
Source V. Hartikainen
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
Remixed from a drawing in 'Line and form', Walter Crane, 1914.
Source Firkin
By popular request, an outline version of the pentagon pattern.
Source Atle Mo
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Remixed from a drawing in 'Line and form", Walter Crane, 1914.
Source Firkin
Prismatic Polka Dots Mark II 2 No Background
Source GDJ
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
A grid of squares with green colours. Since the colours are randomly distributed it is automatically seamless.
Source Firkin
A seamless pattern formed from a square tile. The tile can be retrieved by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
The classic notebook paper with horizontal stripes.
Source Are Sundnes
Hexagonal dark 3D pattern. What more can you ask for?
Source Norbert Levajsics
Real snow that tiles, not easy. This is not perfect, but an attempt.
Source Atle Mo
This background pattern contains a seamless texture of bark. It's not very realistic, but I think it looks quite nice.
Source V. Hartikainen
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
Zero CC tileable ground cracked, crackled, texture, made by me.
Source Sojan Janso
Can’t believe we don’t have this in the collection already! Slick woven pattern with crisp details.
Source Max Rudberg
The tile this is formed from can be retrieved in Inkscape by selecting the rectangle and using shift+alt+i
Source Firkin
If you want png files of this u can download them here : viscious-speed.deviantart.com/gallery/27635117
Source Viscious-Speed
A version without colours blended together to give a different look.
Source Firkin
The image depicts a seamless pattern of a Japanese family crest called "chidori" in Japanese .A chidori in Japanese means a plover in English.
Source Yamachem
Bumps, highlight and shadows – all good things.
Source Badhon Ebrahim