Simple combination of stripy squares with their negatively coloured counterparts
Source Firkin
If you want png files of thisu can download them here :
Source Viscious-Speed
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
The green fibers pattern will work very well in grayscale as well.
Source Matteo Di Capua
The image is a remix of "edo pattern-samekomon".I changed the color of dots from black to white and added BG in light-brown.
Source Yamachem
Seamless pattern the tile for which can be had by using shift-alt-I on the selected rectangle in Inkscape.
Source Firkin
CC0 and a seamless pattern from a tile drawn in Paint.net .
Source SliverKnight
The tile this is formed from can be retrieved in Inkscape by selecting the rectangle and using shift+alt+i
Source Firkin
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Dark squares with some virus-looking dots in the grid.
Source Hugo Loning
The rectangular tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
Can never have too many knitting patterns, especially as nice as this.
Source Victoria Spahn
Sort of reminds me of those old house wallpapers.
Source Tish
This is so subtle you need to bring your magnifier!
Source Carlos Valdez
Prismatic Abstract Line Art Pattern Background 2
Source GDJ
Derived from an image that was uploaded to Pixabay by Kaz
Source Firkin
A floral background formed from numerous clones of flower 117.
Source Firkin
Colorful Floral Background 3 No Black
Source GDJ
The starting point for this was a texture drawn with the 'Radial Colors' plug-in in Paint.net.
Source Firkin
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin