A seamless background drawn in Paint.net and vectorised with Vector Magic. The starting point was a photograph of drinking straws from Pixabay.
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
From a drawing in 'Hubert Montreuil, or the Huguenot and the Dragoon', Francisca Ouvry, 1873.
Source Firkin
CC0 and a seamless pattern from a tile drawn in Paint.net .
Source SliverKnight
A seamless pattern formed from a square tile. To get the tile, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Black And White Floral Pattern Background Inverse
Source GDJ
Nothing like a clean set of bed sheets, huh?
Source Badhon Ebrahim
A seamless pattern of dark bricks. Maybe it's not very realistic, but it looks good in my opinion.
Source V. Hartikainen
Floral patterns will never go out of style, so enjoy this one.
Source Lasma
This is a hot one. Small, sharp and unique.
Source GraphicsWall
To get the tile this is based on select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
To get the tile this is based on select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
The unit cell for this seamless pattern can be had in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin
Found on the ground in french cafe in kunming, Yunnan, china
Source Rejon
Prismatic Groovy Concentric Background
Source GDJ
Very dark pattern with some noise and 45-degree lines.
Source Stefan Aleksić
Simple combination of stripy squares with their negatively coloured counterparts
Source Firkin
A subtle shadowed checkered pattern. Increase the lightness for even more subtle sexiness.
Source Josh Green
Prismatic Geometric Tessellation Pattern 4 No Background
Source GDJ
This one takes you back to math class. Classic mathematic board underlay.
Source Josh Green
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
From a design found in 'History of the Virginia Company of London; with letters to and from the first Colony, never before printed', Edward Neill, 1869.
Source Firkin