A seamless pattern the unit cell for which can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
The image depicts a seamless pattern of pine tree leaves.
Source Yamachem
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
Hexagonal dark 3D pattern. What more can you ask for?
Source Norbert Levajsics
Actually, there's no clouds in it, but I think it looks quite nice.
Source V. Hartikainen
Light gray grunge wall with a nice texture overlay.
Source Adam Anlauf
This makes me wanna shoot some pool! Sweet green pool table pattern.
Source Caveman
This is a remix of "blue wave-seigaiha".I hope this subtle color version of Seigaiha would be suitable for background .
Source Yamachem
Design drawn in Paint.net, vectorised using Vector Magic and finished in Inkscape.
Source Firkin
A seamless texture of worn out "cardboard".
Source V. Hartikainen
If you like it a bit trippy, this wave pattern might be for you.
Source Ian Soper
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
If you need a green background for your blog/website, try this one. Remember that Green Striped Background is seamlessly tileable.
Source V. Hartikainen
Stefan is hard at work, this time with a funky pattern of squares.
Source Stefan Aleksić
Prismatic Polyskelion Pattern No Background
Source GDJ
Otis Ray Redding was an American soul singer-songwriter, record producer, arranger, and talent scout. So you know.
Source Thomas Myrman
Derived from an image that was uploaded to Pixabay by starchim01
Source Firkin
I love cream! 50x50px and lovely in all the good ways.
Source Thomas Myrman
A very slick dark rubber grip pattern, sort of like the grip on a camera.
Source Sinisha
Prismatic Abstract Background Design No Black
Source GDJ
The name is totally random, but hey, it sounds good.
Source Atle Mo
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
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
From a drawing in 'Chambéry à la fin du XIVe siècle', Timoleon Chapperon, 1863.
Source Firkin
Remixed from a PNG that was uploaded to Pixabay by gingertea
Source Firkin