A comeback for you: the popular Escheresque, now in black.
Source Patten
From a drawing in 'Chambéry à la fin du XIVe siècle', Timoleon Chapperon, 1863.
Source Firkin
The basic shapes never get old. Simple triangle pattern.
Source Atle Mo
Sharp pixel pattern looking like some sort of fabric.
Source Dmitry
A repeating background with seamless texture of stone. There haven't been any stone-like backgrounds for a while, so I have decided to create one more. The rest can be found in the appropriate category.
Source V. Hartikainen
Inspired by a pattern found in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892.
Source Firkin
Prismatic Abstract Background Design
Source GDJ
From a drawing in 'In an Enchanted Island', William Mallock, 1892.
Source Firkin
Cubes as far as your eyes can see. You know, because they tile.
Source Jan Meeus
Inspired by an image that was uploaded to Pixabay by geralt
Source Firkin
A simple circle. That’s all it takes. This one is even transparent, for those who like that.
Source Saqib
Seamless Background For Websites. It has a texture similar to cork-board.
Source V. Hartikainen
The image depicts a seamless pattern which includes hexagonally-aligned gourds with BG in light-brown.
Source Yamachem
Adapted from an image that was uploaded to Pixabay by Anerma.
Source Firkin
The tile this is formed from can be retrieved in Inkscape by selecting the rectangle and using shift+alt+i
Source Firkin
From a drawing in 'Resa i Afrika, genom Angola, Ovampo och Damaraland', P. Moller, 1899.
Source Firkin
A new take on the black linen pattern. Softer this time.
Source Atle Mo
An abstract pale yellow paper-like background with stains colored in yellow and green.
Source V. Hartikainen
The image depicts a seamless pattern of pine tree leaves.
Source Yamachem
A comeback for you: the popular Escheresque, now in black.
Source Patten
To get the tile this is based on select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Here's a new paper-like background for free use on personal and commercial projects (this applies to all background patterns here).
Source V. Hartikainen