It has waves, so make sure you don’t get sea sickness.
Source CoolPatterns
To get the tile this is based on select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
Light gray grunge wall with a nice texture overlay.
Source Adam Anlauf
Could remind you a bit of those squares in Super Mario Bros, yeh?
Source Jeff Wall
A playful triangle pattern with different shades of gray.
Source Dimitrie Hoekstra
It’s an egg, in the form of a pattern. This really is 2012.
Source Paul Phönixweiß
Super subtle indeed, a medium gray pattern with tiny dots in a grid.
Source Designova
Background formed from the original with an emboss effect.
Source Firkin
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
From a drawing in 'Navigations de Alouys de Cademoste.-La Navigation du Capitaine Pierre Sintre', Alvise da ca da Mosto, 1895.
Source Firkin
Prismatic Isometric Cube Wireframe Pattern No Background
Source GDJ
Crossing lines with a subtle emboss effect on a dark background.
Source Stefan Aleksić
A free light orange brown wallpaper with vertical stripes designed for use as a tiled background on websites. An yet another background pattern with vertical stripes.
Source V. Hartikainen
From a drawing in 'Real Sailor-Songs', John Ashton, 1891.
Source Firkin
This is so subtle I hope you can see it! Tweak at will.
Source Alexandre Naud
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
This tiled background comes in red and consists of tiles that look like gemstones. It is more for blogs or social profiles, I think.
Source V. Hartikainen
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso