The image is a design of blue glass.How about using it as background image?
Source Yamachem
Remixed from a drawing in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892.
Source Firkin
Another fairly simple design drawn in Paint.net and vectorized in Inkscape.
Source Firkin
Simple gray checkered lines, in light tones.
Source Radosław Rzepecki
Fabric-ish patterns are close to my heart. French Stucco to the rescue.
Source Christopher Buecheler
CC0 and a seamless pattern from a tile drawn in Paint.net .
Source SliverKnight
Pattern Background, Texture, Photoshop Structure style CC0 texture.
Source Darkmoon1968
The unit cell for this seamless pattern can be had in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin
Remixed from a drawing in 'Chambéry à la fin du XIVe siècle', Timoleon Chapperon, 1863.
Source Firkin
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
Not a flat you live inside, like in the UK – but a flat piece of cardboard.
Source Appleshadow
Prismatic Curved Diamond Pattern 4 No Background
Source GDJ
ZeroCC tileable stone texture, edited from pixabay. CC0
Source Sojan Janso
Prismatic Polyskelion Pattern No Background
Source GDJ
From drawing in 'Musings in Maoriland', Thomas Bracken, 1890.
Source Firkin
Bigger is better, right? So here you have some large carbon fiber.
Source Factorio.us Collective
Prismatic Snowflakes Pattern 2 No Background
Source GDJ
Stefan is hard at work, this time with a funky pattern of squares.
Source Stefan Aleksić
It’s like Shine Dotted’s sister, only rotated 45 degrees.
Source mediumidee
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
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
A seamless background texture of old cardboard.
Source V. Hartikainen
Remixed from a design seen in 'Burghley. The Life of William Cecil', William Charlton, 1857
Source Firkin
Classic 45-degree pattern, light version.
Source Luke McDonald
I guess this is inspired by the city of Ravenna in Italy and its stone walls.
Source Sentel