The image depicts a seamless pattern of a tortoise in tortoiseshell (hexagon).
Source Yamachem
It’s okay to be square! A nice light gray pattern with random squares.
Source Waseem Dahman
From a drawing in 'In an Enchanted Island', William Mallock, 1892.
Source Firkin
Pattern #100! A black classic knit-looking pattern.
Source Factorio.us Collective
From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
The name alone is awesome, but so is this sweet dark pattern.
Source Federica Pelzel
To get the tile this is based on, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
Number 3 in a series of 5 beautiful patterns. Can be found in colors on the submitter’s website.
Source Janos Koos
One more sharp little tile for you. Subtle circles this time.
Source Blunia
Prismatic Floral Background No Black
Source GDJ
This was submitted in a beige color, hence the name. Now it’s a gray paper pattern.
Source Konstantin Ivanov
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
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
Classic vertical lines, in all its subtlety.
Source Cody L
Vector version of a png that was uploaded to Pixabay by pencilparker
Source Firkin
Number 2 in a series of 5 beautiful patterns. Can be found in colors on the submitter’s website.
Source Janos Koos
Remixed from a JPG that was uploaded to Pixabay by susanlu4esm
Source Firkin
Here's an yet another background for websites, with a seamless texture of wood planks this time.
Source V. Hartikainen