From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
Sounds French. Some 3D square diagonals, that’s all you need to know.
Source Graphiste
From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
A seamless pattern made from the gold Penrose triangle by GDJ and the two remixes
Source Firkin
This is a remix of "blue wave-seigaiha".I hope this subtle color version of Seigaiha would be suitable for background .
Source Yamachem
The image depicts a seamless pattern of a tortoise in tortoiseshell (hexagon).
Source Yamachem
Number 5 in a series of 5 beautiful patterns. Can be found in colors on the submitter’s website.
Source Janos Koos
Sharp pixel pattern, just like the good old days.
Source Paridhi
The image depicts polka dot seamless pattern.
Source Yamachem
A seamless pattern formed from a tile made from ornament 22. To get the tile, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Prismatic Basic Pattern 2 No Background
Source GDJ
A bit of scratched up grayness. Always good.
Source Dmitry
Background Wall, Art Abstract, Watercolor Vintage style CC0 texture.
Source Ractapopulous
This is a semi-dark pattern, sort of linen-y.
Source Sagive SEO
This background image has seamless texture that resembles a surface of gray stone.
Source V. Hartikainen
Drawn in Paint.net using the kaleidoscope plug-in and vectorised.
Source Firkin
New paper pattern with a slightly organic feel to it, using some thin threads.
Source Atle Mo
Remixed from a drawing in 'The Canadian horticulturist', 1892
Source Firkin
I skipped number 3, because it wasn’t all that great. Sorry.
Source Dima Shiper