An abstract texture of water. It's not perfect, but will do. You may download if you like it.
Source V. Hartikainen
Remixed from a design seen on Pixabay. The basic tile can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
To get the tile this is formed from select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Remixed from a drawing in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892. The tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
Crossing lines with a subtle emboss effect on a dark background.
Source Stefan Aleksić
A hint of orange color, and some crossed and embossed lines.
Source Adam Anlauf
This seamless pattern consists of a blue grid on a yellow background.
Source V. Hartikainen
Vertical lines with a bumpy, yet crisp, feel to it.
Source Raasa
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
A pattern formed from a squared tile. The tile can be accessed in Inkscape by selecting the rectangle and using shift-alt-i.
Source Firkin
A seamless background of warped stripes on paper.
Source V. Hartikainen
The image depicts the Japanese Edo pattern called "seigaiha" or "青海波" meaning "blue -sea- wave".I hope it's suitable for the summer season.
Source Yamachem
Formed from a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
This is the remix of "blue wave-seigaiha".The image depicts a seamless pattern of the front upper part of Japanese five yen coin which is used currently.This design represents a rice with ripe golden ears.
Source Yamachem
Retro Circles Background 7 No Black
Source GDJ
A huge one at 800x600px. Made from a photo I took going home after work.
Source Atle Mo
From a drawing in 'Gately's World's Progress', Charles Beale, 1886.
Source Firkin
The name tells you it has curves. Oh yes, it does!
Source Peter Chon
Remixed from a PNG that was uploaded to Pixabay by VictorianLady
Source Firkin
Turn your site into a dragon with this great scale pattern.
Source Alex Parker
Remixed from an image that was uploaded to Pixabay by Pixeline
Source Firkin
Prismatic Rounded Squares Grid 4 No Background
Source GDJ
Prismatic Groovy Concentric Background 4 No Black
Source GDJ
Prismatic Hypnotic Pattern 2 No Background
Source GDJ
The unit cell for this seamless pattern can be had in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin