CC0 and a seamless pattern from a tile drawn in Paint.net .
Source SliverKnight
Utilising some flowers from Almeidah. To get the unit tile, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
A subtle shadowed checkered pattern. Increase the lightness for even more subtle sexiness.
Source Josh Green
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
It’s a hole, in a pattern. On your website. Dig it!
Source Josh Green
Derived from an image that was uploaded to Pixabay by mdmelo.
Source Firkin
Free tiled background with colorful stripes and white splatter.
Source V. Hartikainen
From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
A frame using leaves from an image that was uploaded to Pixabay by mayapujiati
Source Firkin
A seamless stone-like background for blogs or any other type of websites.
Source V. Hartikainen
From a drawing in 'Danmarks Riges Historie af J. Steenstrup, Kr. Erslev, A. Heise, V. Mollerup, J. A. Fridericia, E. Holm, A. D. Jørgensen', 1897.
Source Firkin
From a drawing in 'Les Chroniqueurs de l'Histoire de France depuis les origines jusqu'au XVIe siècle', Henriette Witt, 1884.
Source Firkin
Prismatic Curved Diamond Pattern 8 No Background
Source GDJ
Oh yes, it happened! A pattern in full color.
Source Atle Mo