Not strictly seamless in that opposite edges are not identical. But they do marry up to make an interesting pattern
Source Firkin
If you want png files of this u can download them here : viscious-speed.deviantart.com/gallery/27635117
Source Viscious-Speed
To celebrate the new feature, we need some sparkling diamonds.
Source Atle Mo
Utilising some flowers from Almeidah. To get the unit tile, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
The classic notebook paper with horizontal stripes.
Source Are Sundnes
From a drawing in 'At home', J. Sowerby, J. Crane and T. Frederick, 1881.
Source Firkin
Remixed from a raster on Pixabay, that was uploaded by ArtsyBee.
Source Firkin
You know I’m a sucker for these. Well-crafted paper pattern.
Source Mihaela Hinayon
A subtle shadowed checkered pattern. Increase the lightness for even more subtle sexiness.
Source Josh Green
And some more testing, this time with Seamless Studio. It’s Robots FFS!
Source Seamless Studio
A light gray wall or floor (you decide) of concrete.
Source Atle Mo
A seamless pattern from a tile made from a jpg on Pixabay. To get the tile select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
Remixed from a drawing in 'Works. Popular edition', John Ruskin, 1886.
Source Firkin
From a drawing in 'In an Enchanted Island', William Mallock, 1892.
Source Firkin
Light honeycomb pattern made up of the classic hexagon shape.
Source Federica Pelzel
From a drawing in 'At home', J. Sowerby, J. Crane and T. Frederick, 1881.
Source Firkin
The tile can be had by using shift+alt+i on the selected rectangle in Inkscape
Source Firkin
Prismatic Rounded Squares Grid 3 No Background
Source GDJ
Fix and cc0 to get the tile this is based on.
Source SliverKnight
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
This was formed by distorting an image of a background on Pixabay.
Source Firkin