This is so subtle I hope you can see it! Tweak at will.
Source Alexandre Naud
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
Zero CC tileable hard cover red book, scanned and made by me. CC0
Source Sojan Janso
Abstract Geometric Monochrome Pattern Prismatic No Background
Source GDJ
Remixed from a drawing in 'Chambéry à la fin du XIVe siècle', Timoleon Chapperon, 1863.
Source Firkin
From a drawing in 'Resa i Afrika, genom Angola, Ovampo och Damaraland', P. Moller, 1899.
Source Firkin
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
Dark wooden pattern, given the subtle treatment. based on texture from Cloaks.
From a drawing in 'Codogno e il suo territorio nella cronaca e nella storia'', Gio and Giarella Cairo, 1897.
Source Firkin
Smooth Polaroid pattern with a light blue tint.
Source Daniel Beaton
From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Number 3 in a series of 5 beautiful patterns. Can be found in colors on the submitter’s website.
Source Janos Koos
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
A seamless pattern from a tile drawn in Paint.net and vectorised in Vector Magic
Source Firkin
Cubes as far as your eyes can see. You know, because they tile.
Source Jan Meeus
Floral patterns might not be the hottest thing right now, but you never know when you need it!
Source Lauren
Remixed from a design seen on Pixabay. The basic tile can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
Used a cherry by doctormo to make this seamless pattern
Source Firkin
The tile this is based on can be retrieved by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Square design drawn in Paint.net and vectorized in Vector Magic.
Source Firkin
A subtle shadowed checkered pattern. Increase the lightness for even more subtle sexiness.
Source Josh Green
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
A cute x, if you need that sort of thing.
Source Juan Scrocchi