This is indeed a bit strange, but here’s to the crazy ones!
Source Christopher Buecheler
Basket Fibers, Basket Texture, Braid Background style CC0 texture.
Source 1A-Photoshop
Derived from an image that was uploaded to Pixabay by starchim01
Source Firkin
Background Wall, Art Abstract, Blue Well & CC0 texture.
Source Ractapopulous
A yellow tiled background... Blurriness, bokeh effect and rectangles pattern in one mix.
Source V. Hartikainen
Prismatic Curved Diamond Pattern 7 No Background
Source GDJ
A background pattern with a look of rough fabric.
Source V. Hartikainen
An alternative colour scheme to the original seamless pattern.
Source Firkin
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
Never out of fashion and so much hotter than the 45º everyone knows, here is a sweet 60º line pattern.
Source Atle Mo
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Remixed from a drawing in 'Works. Popular edition', John Ruskin, 1886.
Source Firkin
Prismatic Geometric Pattern Background No Black
Source GDJ
Not even 1kb, but very stylish. Gray thin lines.
Source Struck Axiom
A background formed from an image of an old tile on the New York Metropolitan Museum of Art website. To get the base tile, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
Prismatic Polka Dots Mark II 3 No Background
Source GDJ
Dark squares with some virus-looking dots in the grid.
Source Hugo Loning
Sharp pixel pattern, just like the good old days.
Source Paridhi
Prismatic Geometric Pattern Background 2
Source GDJ
Prismatic Curved Diamond Pattern 5 No Background
Source GDJ
A free seamless background image with a texture of dark red "canvas". It should look very nice on web sites.
Source V. Hartikainen
The classic 45-degree diagonal line pattern, done right.
Source Jorick van Hees