A free seamless background image with a texture of dark red "canvas". It should look very nice on web sites.
Source V. Hartikainen
Colour version that is close to the original drawing uploaded to Pixabay by pencilparker.
Source Firkin
A mid-tone gray pattern with some cement looking texture.
Source Hendrik Lammers
A seamless pattern formed from a square tile. To get the tile, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Original minus the background
Source Firkin
Colorful Floral Background 3 No Black
Source GDJ
One more from Badhon, sharp horizontal lines making an embossed paper feeling.
Source Badhon Ebrahim
Background Wall, Art Abstract, Watercolor Vintage style CC0 texture.
Source Ractapopulous
Prismatic Abstract Geometric Background 2 No Black
Source GDJ
This one takes you back to math class. Classic mathematic board underlay.
Source Josh Green
Background Wall, Art Abstract, Blue Well & CC0 texture.
Source Ractapopulous
Don’t look at this one too long if you’re high on something.
Source Luuk van Baars
A seamless background drawn in Paint.net and vectorised with Vector Magic. The starting point was a photograph of drinking straws from Pixabay.
Source Firkin
The classic subtle pattern. Sort of wall/brick looking. Or moon-looking?
Source Joel Klein
From a drawing in 'Navigations de Alouys de Cademoste.-La Navigation du Capitaine Pierre Sintre', Alvise da ca da Mosto, 1895.
Source Firkin
This one is rather fun and playful. The 2X could be used at 1X too!
Source Welsley
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
One more in the line of patterns inspired by Japanese/Asian styles. Smooth.
Source Kim Ruddock
Did some testing with Repper Pro tonight, and this gray mid-tone pattern came out.
Source Atle Mo
Detailed but still subtle and quite original. Lovely gray shades.
Source Kim Ruddock
A background pattern with blue on white vertical stripes.
Source V. Hartikainen
Remixed from a design seen on Pixabay. The basic tile can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Abstract Tiled Background Extended 6
Source GDJ