Looks a bit like concrete with subtle specks spread around the pattern.
Source Mladjan Antic
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
ZeroCC tileabel stone granite texture, edited from pixabay. CC0
Source Sojan Janso
Wasn't satisfied with the original's colouring. Too much component transfer and colormatrixes yet the results are lacking a bit. So this time it is a simple black to transparent fade, making it possible remixing easily once there will be other blending modes supported as well. Probably in inkscape 0.92.
Source Lazur URH
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Prismatic Polka Dots Mark II No Background
Source GDJ
Seamless SVG vector and JPG backgrounds with faded diagonal stripes. The colors are editable.
Source V. Hartikainen
This one looks like a cork panel. Feel free to use it as a tiled background on your blog or website.
Source V. Hartikainen
This is a seamless pattern of a woody texture.The original image is here:https://pixabay.com/ja/users/ClassicallyPrinted-1302233/
Source Yamachem
emixed from a JPG that was uploaded to Pixabay by Kyotime
Source Firkin
Drawn in Paint.net and vectorised in Vector Magic
Source Firkin
Formed by distorting the inside front cover of 'Diversæ insectarum volatilium : icones ad vivum accuratissmè depictæ per celeberrimum pictorem', Jacob Hoefnagel, 1630.
Source Firkin
Prismatic Groovy Concentric Background 2
Source GDJ
Remixed from a drawing in 'The March of Loyalty', Letitia MacClintock, 1884.
Source Firkin
Design drawn in Paint.net, vectorised using Vector Magic and finished in Inkscape.
Source Firkin
A dark gray, sandy pattern with small light dots, and some angled strokes.
Source Atle Mo
Lovely pattern with some good-looking non-random noise lines.
Source Zucx
Sharp diamond pattern. A small 24x18px tile.
Source Tom Neal
Pattern formed from simple shapes. Black version.
Source Firkin
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
A seamless pattern formed from miutopia's cakes on a tablecloth.
Source Firkin