Heavy depth and shadows here, but might work well on some mobile apps.
Source Damian Rivas
The tile for this is based on a repeating unit close to a design on Pixabay. It can be had by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
Not a flat you live inside, like in the UK – but a flat piece of cardboard.
Source Appleshadow
This is the remix of "Strawberry Pattern Background" uploaded by "GDJ". Thanks. I realigned strawberries so as to get seamless and changed the BG color.
Source Yamachem
Seamless pattern formed from a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
Prismatic Polyskelion Pattern No Background
Source GDJ
This was formed by distorting an image of a background on Pixabay.
Source Firkin
An attempt for cleaning up the original image in a few steps.
Source Lazur URH
Black brick wall pattern. Brick your site up!
Source Alex Parker
Seamless pattern formed from a tile that can be had by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
The image is a seamless pattern of a fishnet.
Source Yamachem
A repeating graphic with ancient pattern. I came up with this name/title at last minute, so you may find that there is very little of ancientness in this pattern after all.
Source V. Hartikainen
Can’t believe we don’t have this in the collection already! Slick woven pattern with crisp details.
Source Max Rudberg
Remixed from a drawing in 'Line and form', Walter Crane, 1914.
Source Firkin
Nice and simple crossed lines in dark gray tones.
Source Stefan Aleksić
From a drawing in 'Navigations de Alouys de Cademoste.-La Navigation du Capitaine Pierre Sintre', Alvise da ca da Mosto, 1895.
Source Firkin
Abstract Geometric Monochrome Pattern Prismatic No Background
Source GDJ
Turn your site into a dragon with this great scale pattern.
Source Alex Parker
This was submitted in a beige color, hence the name. Now it’s a gray paper pattern.
Source Konstantin Ivanov
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
A seamless texture of worn out "cardboard".
Source V. Hartikainen
That’s what it is, a dark dot. Or sort of carbon looking.
Source Tsvetelin Nikolov
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
I skipped number 3, because it wasn’t all that great. Sorry.
Source Dima Shiper
Kaleidoscope Prismatic Abstract No Background
Source GDJ