Simple combination of stripy squares with their negatively coloured counterparts
Source Firkin
Not sure if this is related to the Nami you get in Google image search, but hey, it’s nice!
Source Dertig Media
Dark squares with some virus-looking dots in the grid.
Source Hugo Loning
Derived from a drawing in 'The Murmur of the Shells', Samuel Cowen, 1879.
Source Firkin
Prismatic Groovy Concentric Background 5
Source GDJ
Drawn in Paint.net using the kaleidoscope plug-in and vectorised.
Source Firkin
To get the tile this is based on select the rectangle in Inkscape and use shift-alt-i
Source Firkin
From a drawing in 'Prose and Verse ', William Linton, 1836.
Source Firkin
Background Wall, Art Abstract, Block Well & CC0 texture.
Source Ractapopulous
CC0 and a seamless pattern from a tile drawn in Paint.net .
Source SliverKnight
The perfect pattern for all your blogs about type, or type-related matters.
Source Atle Mo
A seamless pattern formed from a tile that can be had in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin
Derived from an image that was uploaded to Pixabay by Kaz
Source Firkin
Abstract Ellipses Background Grayscale
Source GDJ
And some more testing, this time with Seamless Studio. It’s Robots FFS!
Source Seamless Studio
It looks like a polished stone surface to me. Download it for free, as always.
Source V. Hartikainen
Pixel by pixel, sharp and clean. Very light pattern with clear lines.
Source M.Ashok
Not strictly seamless in that opposite edges are not identical. But they do marry up to make an interesting pattern
Source Firkin
From a drawing in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892.
Source Firkin
A seamless pattern that includes the original tile (go to Objects / Pattern / Pattern To Objects in Inkscape's menu to extract it).
Source GDJ
Prismatic Groovy Concentric Background 5 No Black
Source GDJ
A bit strange this one, but nice at the same time.
Source Diogo Silva
I know there is one here already, but this is sexy!
Source Gjermund Gustavsen