From a drawing in 'Maidenhood; or, the Verge of the Stream', Laura Jewry, 1876.
Source Firkin
Remixed from an image that was uploaded to Pixabay by Pixeline
Source Firkin
Light gray pattern with an almost wall tile-like appearance.
Source Markus Tinner
Derived from an image that was uploaded to Pixabay by Darkmoon1968
Source Firkin
Derived from an image that was uploaded to Pixabay by darkmoon1968
Source Firkin
Prismatic Polka Dots Mark II 3 No Background
Source GDJ
The image depicts a seamless pattern of a tortoise in tortoiseshell (hexagon).
Source Yamachem
This background image has seamless texture that resembles a surface of gray stone.
Source V. Hartikainen
From a drawing in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892.
Source Firkin
Never out of fashion and so much hotter than the 45º everyone knows, here is a sweet 60º line pattern.
Source Atle Mo
Prismatic Groovy Concentric Background 2 No Black
Source GDJ
Actually, there's no clouds in it, but I think it looks quite nice.
Source V. Hartikainen
Abstract Arbitrary Geometric Background derived from an image on Pixabay.
Source GDJ
Zero CC tileable ground cracked, crackled, texture, made by me.
Source Sojan Janso
A very dark spotted twinkle pattern for your twinkle needs.
Source Badhon Ebrahim
Prismatic Geometric Pattern Background No Black
Source GDJ
The name tells you it has curves. Oh yes, it does!
Source Peter Chon
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
A pattern drawn in Paint.net and vectorized in Vector Magic.
Source Firkin
Light square grid pattern, great for a “DIY projects” sort of website, maybe?
Source Rafael Almeida
Remixed from a design seen in 'Burghley. The Life of William Cecil', William Charlton, 1857. The tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin