It looks like a polished stone surface to me. Download it for free, as always.
Source V. Hartikainen
Remixed from a drawing in 'Line and form', Walter Crane, 1914.
Source Firkin
A background pattern with blue on white vertical stripes.
Source V. Hartikainen
This is so subtle you need to bring your magnifier!
Source Carlos Valdez
Prismatic Rounded Squares Grid 4 No Background
Source GDJ
That’s what it is, a dark dot. Or sort of carbon looking.
Source Tsvetelin Nikolov
Oh yes, it happened! A pattern in full color.
Source Atle Mo
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
Can never have too many knitting patterns, especially as nice as this.
Source Victoria Spahn
Paper pattern with small dust particles and 45-degree strokes.
Source Atle Mo
Not a flat you live inside, like in the UK – but a flat piece of cardboard.
Source Appleshadow
Here is a new seamless wood texture for using as blog or website backgrounds.
Source V. Hartikainen
Seamless pattern formed from a tile that can be had by selecting the rectangle in Inkscape 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
From a drawing in 'Danmarks Riges Historie af J. Steenstrup, Kr. Erslev, A. Heise, V. Mollerup, J. A. Fridericia, E. Holm, A. D. Jørgensen', 1897.
Source Firkin
From a drawing in 'Heroes of North African Discovery', Nancy Meugens, 1894.
Source Firkin
Prismatic Polka Dots Mark II 3 No Background
Source GDJ
This is the third pattern called Dark Denim, but hey, we all love them!
Source Brandon Jacoby
Heavy depth and shadows here, but might work well on some mobile apps.
Source Damian Rivas
Number 2 in a series of 5 beautiful patterns. Can be found in colors on the submitter’s website.
Source Janos Koos
Seamless pattern formed from a tile that can be extracted by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin