A good starting point for a cardboard pattern. This would work well in a variety of colors.
Source Atle Mo
A light gray fabric pattern with faded vertical stripes.
Source V. Hartikainen
To get the tile this is based on select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Remixed from a drawing in 'The March of Loyalty', Letitia MacClintock, 1884.
Source Firkin
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Pattern Background, Texture, Photoshop Structure style CC0 texture.
Source Darkmoon1968
A bit strange this one, but nice at the same time.
Source Diogo Silva
Dark, square, clean and tidy. What more can you ask for?
Source Jaromír Kavan
A seamless pattern formed from a square tile. The tile can be retrieved by selecting the rectangle in Inkscape and using shift-alt-I.
Source Firkin
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Colour version that is close to the original drawing uploaded to Pixabay by pencilparker.
Source Firkin
A seamless pattern created from a square tile. To get the tile, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Inspired by an image that was uploaded to Pixabay by geralt
Source Firkin
Sort of like the Photoshop transparent background, but better!
Source Alex Parker
From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Design drawn in Paint.net, vectorised using Vector Magic and finished in Inkscape.
Source Firkin
Prismatic Floral Background No Black
Source GDJ
The act or state of corrugating or of being corrugated, a wrinkle; fold; furrow; ridge.
Source Anna Litvinuk
Not sure if this is related to the Nami you get in Google image search, but hey, it’s nice!
Source Dertig Media
ZeroCC tileable beechwood wood texture, generated in Neo Texture Edit by me. CC0
Source Sojan Janso
Abstract Geometric Monochrome Pattern Prismatic No Background
Source GDJ
One more brick pattern. A bit more depth to this one.
Source Benjamin Ward