Used correctly, this could be nice. Used in a bad way, all hell will break loose.
Source Atle Mo
A nice and simple white rotated tile pattern.
Source Another One
The image depicts a seamless pattern of a snow crystal.I referred to a book called ”sekka-zusetsu” or "雪華図説" which means an illustrated explanation about snow crystals.This book was published in 1832 (天保3年) or Edo period.For more about "雪華図説",see here:dl.ndl.go.jp/info:ndljp/pid/2536975
Source Yamachem
Here's an yet another background for websites, with a seamless texture of wood planks this time.
Source V. Hartikainen
Colour version of a pattern that came out of playing with the 'light rays' plug-in for Paint.net
Source Firkin
A classic dark tile for a bit of vintage darkness.
Source Listvetra
Actually remixed from a pattern on Pixabay. But then noticed a very similar one on Openclipart.org uploaded by btj51q2.
Source Firkin
Submitted in a cream color, but you know how I like it.
Source Devin Holmes
Prismatic Polka Dots 3 No Background
Source GDJ
I love cream! 50x50px and lovely in all the good ways.
Source Thomas Myrman
On a large canvas you can see it tiling, but used on smaller areas, it’s beautiful.
Source Paul Phönixweiß
A seamless background pattern with impressed gray dots.
Source V. Hartikainen
Background formed from the iconic plastic construction bricks that gave me endless hours of fun when I was a lad.
Source Firkin
From a drawing in 'La Principauté de Liège et les Pays-Bas au XVIe siècle', Société des Bibliophiles Liégeois ,1887.
Source Firkin
Remixed from a drawing in 'Paul's Sister', Frances Peard, 1889.
Source Firkin
Light honeycomb pattern made up of the classic hexagon shape.
Source Federica Pelzel
White handmade paper pattern with small bumps.
Source Marquis
A seamless striped fabric-like texture colored in a dark reddish brown color.
Source V. Hartikainen
Drawn in Paint.net using the kaleidoscope plug-in and vectorised.
Source Firkin
From a design in 'Storia del Palazzo Vecchio in Firenze', Aurelio Gotti, 1889.
Source Firkin
Retro Circles Background 5 No Black
Source GDJ
This background pattern looks like bamboo to me. Feel free to download it for your website (for your blog perhaps?).
Source V. Hartikainen
A very dark spotted twinkle pattern for your twinkle needs.
Source Badhon Ebrahim