This was formed by distorting an image of a background on Pixabay.
Source Firkin
This is a seamless pattern of regular hexagon which has a honeycomb structure.
Source Yamachem
Bright Multicolored Floral Background by Karen Arnold from PDP.
Source GDJ
Prismatic Groovy Concentric Background 2
Source GDJ
A seamless texture of worn out "cardboard".
Source V. Hartikainen
A series of 5 patterns. That’s what the P stands for, if you didn’t guess it.
Source Dima Shiper
The rectangular tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
Prismatic Basic Pattern 2 No Background
Source GDJ
Remixed from an image that was uploaded to Pixabay by KirstenStar
Source Firkin
Dark, crisp and subtle. Tiny black lines on top of some noise.
Source Wilmotte Bastien
A grid of squares with green colours. Since the colours are randomly distributed it is automatically seamless.
Source Firkin
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
A tile-able background for websites with paper-like texture and a grid pattern layered on top of it.
Source V. Hartikainen
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
A repeating background for websites with a texture of black groove stripes.
Source V. Hartikainen
Number five from the same submitter, makes my job easy.
Source Dima Shiper
Remixed from a JPG that was uploaded to Pixabay by susanlu4esm
Source Firkin
A seamless pattern created from a square tile. To get the tile, select the pattern in Inkscape and use shift+alt+i.
Source Firkin
A nice one indeed, but I have a feeling we have it already? If you spot a copy, let me know on Twitter.
Source Graphiste
Not a flat you live inside, like in the UK – but a flat piece of cardboard.
Source Appleshadow
Nicely executed tiling for an interesting pattern.
Source Ignasi Àvila Padró