From a drawing in 'Cowdray: the history of a great English House', Julia Roundell, 1884.
Source Firkin
Prismatic Groovy Concentric Background 4
Source GDJ
One more sharp little tile for you. Subtle circles this time.
Source Blunia
From a drawing in 'In an Enchanted Island', William Mallock, 1892.
Source Firkin
Prismatic Isometric Cube Extra Pattern No Background
Source GDJ
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
Not even 1kb, but very stylish. Gray thin lines.
Source Struck Axiom
Actually, there's no clouds in it, but I think it looks quite nice.
Source V. Hartikainen
Prismatic Abstract Geometric Background 4
Source GDJ
A seamless pattern formed from a tile that can be had in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin
You could get a bit dizzy from this one, but it might come in handy.
Source Dertig Media
Prismatic Snowflakes Pattern 3 No Background
Source GDJ
This one is super crisp at 2X. Lined paper with some dust and scratches.
Source HQvectors
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Brushed aluminum, in a bright gray version. Lovely 2X as well.
Source Andre Schouten
This was submitted in a beige color, hence the name. Now it’s a gray paper pattern.
Source Konstantin Ivanov
Looks like an old rug or a computer chip.
Source Patutin Sergey
Background formed from the original with an emboss effect
Source GDJ
Dark squares with some virus-looking dots in the grid.
Source Hugo Loning
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
It has waves, so make sure you don’t get sea sickness.
Source CoolPatterns