I guess this is inspired by the city of Ravenna in Italy and its stone walls.
Source Sentel
A seamless chequerboard pattern formed from a tile that can be had in Inkscape by selecting the rectangle and using shift+alt+i. Alternative colour scheme.
Source Firkin
Prismatic Abstract Geometric Background 4 No Black
Source GDJ
From a drawing in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892.
Source Firkin
Zero CC tileable Crackled Cement (streaks) texture, photographed and made by me. CC0
Source Sojan Janso
ZeroCC tileable mossy (lichen) stone texture, edited from pixabay. CC0
Source Sojan Janso
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
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Here's a quite bright pink background pattern for use on websites. It doesn't look like a real fur, but it definitely resembles one.
Source V. Hartikainen
The Grid. A digital frontier. I tried to picture clusters of information as they traveled through the computer.
Source Haris Šumić
Same as the black version, but now in shades of gray. Very subtle and fine grained.
Source Atle Mo
A light background pattern with diagonal stripes. Here's a simple light striped background for you.
Source V. Hartikainen
A free seamless background texture that looks like a brown stone wall.
Source V. Hartikainen
Prismatic Polka Dots Mark II No Background
Source GDJ
Basket Fibers, Basket Texture, Braid Background style CC0 texture.
Source 1A-Photoshop
Zero CC tileable dry grass texture, photographed and made by me. CC0
Source Sojan Janso
A seamless pattern from a tile made from a jpg on Pixabay. To get the tile select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
Nothing like a clean set of bed sheets, huh?
Source Badhon Ebrahim
A very dark spotted twinkle pattern for your twinkle needs.
Source Badhon Ebrahim
Based on several public domain drawings on Wikimedia Commons. This was formed from a rectangular tile. The tile can be accessed in Inkscape by selecting the rectangle and using shift-alt-i.
Source Firkin
You know, tiny and sharp. I’m sure you’ll find a use for it.
Source Atle Mo