Heavy depth and shadows here, but might work well on some mobile apps.
Source Damian Rivas
From a drawing in 'Friend or Fortune? The story of a strange year', Robert Overton, 1897.
Source Firkin
Prismatic Curved Diamond Pattern No Background
Source GDJ
A seamless pattern formed from a tile made from ornament 22. To get the tile, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
A free background image with a seamless texture of cardboard. This texture of cardboard looks quite realistic, especially when is actually tiled.
Source V. Hartikainen
The unit cell for this seamless pattern can be had in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin
Bigger is better, right? So here you have some large carbon fiber.
Source Factorio.us Collective
To get the tile this is made up from select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
An aged paper background tile with smeared and pressed text.
Source V. Hartikainen
More Japanese-inspired patterns, Gold Scales this time.
Source Josh Green
Zero CC tileable bark texture, photographed and made by me. CC0
Source Sojan Janso
Not the most creative name, but it’s a good all-purpose light background.
Source Dmitry
Background Wall, Art Abstract, Block Well & CC0 texture.
Source Ractapopulous
From a drawing in 'From Snowdon to the Sea. Striking stories of North and South Wales', Marie Trevelyan, 1895.
Source Firkin
This was submitted in a beige color, hence the name. Now it’s a gray paper pattern.
Source Konstantin Ivanov
The tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
Prismatic Floral Background No Black
Source GDJ
The tile this is based on can be retrieved by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
A seamless pattern the starting point for which was a 'rainbow twist' texture in Paint.net.
Source Firkin
A smooth mid-tone gray, or low contrast if you will, linen pattern.
Source Jordan Pittman
Prismatic Hypnotic Pattern 2 No Background
Source GDJ
This background pattern contains worn out colorful stripes as a texture.
Source V. Hartikainen
Prismatic Groovy Concentric Background 2 No Black
Source GDJ
This one is amazing, truly original. Go use it!
Source Viahorizon
To get the tile this is formed from select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
The unit cell for this seamless pattern can be had in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin