From a drawing in 'The Quiver of Love', Walter Crane, 1876
Source Firkin
A seamless pattern based on a square tile that can be retrieved in Inkscape by selecting the rectangle and using shift-alt-i.
Source Firkin
Some rectangles, a bit of dust and grunge, plus a hint of concrete.
Source Atle Mo
Hexagonal dark 3D pattern. What more can you ask for?
Source Norbert Levajsics
Nasty or not, it’s a nice pattern that tiles. Like they all do.
Source Badhon Ebrahim
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
The image is a design of blue glass.How about using it as background image?
Source Yamachem
Prismatic Hypnotic Pattern No Background
Source GDJ
Remixed from an image on Pixabay, the original having been uploaded by darkmoon1968.
Source Firkin
Background Wall, Art Abstract, Block Well & CC0 texture.
Source Ractapopulous
Detailed but still subtle and quite original. Lovely gray shades.
Source Kim Ruddock
Some more diagonal lines and noise, because you know you want it.
Source Atle Mo
From a drawing in 'At home', J. Sowerby, J. Crane and T. Frederick, 1881.
Source Firkin
An abstract texture of black metal pipes (seamless).
Source V. Hartikainen
Psychedelic Geometric Background No Black
Source GDJ
The tile this is based on can be retrieved by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
Looks like a technical drawing board: small squares forming a nice grid.
Source We Are Pixel8
This reminds me of Game Cube. A nice light 3D cube pattern.
Source Sander Ottens
A seamless pattern based on a tile that can be achieved by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Prismatic Snowflakes Pattern 2 No Background
Source GDJ