Background Wall, Art Abstract, Watercolor Vintage style CC0 texture.
Source Ractapopulous
Recreated from a pattern found in 'Az Osztrák-Magyar Monarchia irásban és képben', 1882. To get the tile this is based on select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Derived from an image that was uploaded to Pixabay by mdmelo.
Source Firkin
Same classic 45-degree pattern, dark version.
Source Luke McDonald
Prismatic Geometric Pattern Background 2
Source GDJ
CC0 and a seamless pattern from a tile drawn in Paint.net .
Source SliverKnight
Derived from an image that was uploaded to Pixabay by Darkmoon1968
Source Firkin
Number 4 in a series of 5 beautiful patterns. Can be found in colors on the submitter’s website.
Source Janos Koos
This is so subtle you need to bring your magnifier!
Source Carlos Valdez
More carbon fiber for your collections. This time in white or semi-dark gray.
Source Badhon Ebrahim
Some rectangles, a bit of dust and grunge, plus a hint of concrete.
Source Atle Mo
Embossed lines and squares with subtle highlights.
Source Alex Parker
Derived from a drawing in 'The Murmur of the Shells', Samuel Cowen, 1879.
Source Firkin
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
This one is so simple, yet so good. And you know it. Has to be in the collection.
Source Gluszczenko
The tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin