A seamless pattern formed from a square tile. To get the tile, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
A beautiful dark padded pattern, like an old classic sofa.
Source Chris Baldie
The unit cell for this seamless pattern can be had in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin
The green fibers pattern will work very well in grayscale as well.
Source Matteo Di Capua
Number five from the same submitter, makes my job easy.
Source Dima Shiper
Lovely light gray floral motif with some subtle shades.
Source GraphicsWall
Beautiful dark noise pattern with some dust and grunge.
Source Vincent Klaiber
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Remixed from an image on Pixabay, the original having been uploaded by darkmoon1968.
Source Firkin
Prismatic Polyskelion Pattern No Background
Source GDJ
Prismatic Abstract Background Design No Black
Source GDJ
Lovely pattern with some good-looking non-random noise lines.
Source Zucx
A topographic map like this has actually been requested a few times, so here you go!
Source Sam Feyaerts
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
Bit of a strange name on this one, but still nice. Tiny gray square things.
Source Carlos Valdez
To get the tile this is based on, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
Prismatic Curved Diamond Pattern 5 No Background
Source GDJ
A browner version of the original weathered fence texture.
Source Firkin
Adapted heavily from a JPG that was uploaded to Pixabay by Viscious-Speed.
Source Firkin