CC0 and a seamless pattern from a tile drawn in Paint.net .
Source SliverKnight
A seamless pattern from a tile made from a jpg on Pixabay. To get the tile select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
The unit cell for this seamless pattern can be had in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin
The file was named striped lens, but hey – Translucent Fibres works too.
Source Angelica
Small dots with minor circles spread across to form a nice mosaic.
Source John Burks
A repeating background of beige (or is it more vanilla yellow) textured stripes. One more background with stripes.
Source V. Hartikainen
A seamless texture of an abstract wall colored in shades of light orange brown.
Source V. Hartikainen
A new one called white wall, not by me this time.
Source Yuji Honzawa
A pale olive green background with a seamless texture.
Source V. Hartikainen
A free repetitive background with a dark concrete wall like texture. This one may be used in dark web site designs.
Source V. Hartikainen
Derived from an image that was uploaded to Pixabay by Kaz
Source Firkin
I skipped number 3, because it wasn’t all that great. Sorry.
Source Dima Shiper
ZeroCC tileable moss texture, photographed and made by me. CC0
Source Sojan Janso
A very slick dark rubber grip pattern, sort of like the grip on a camera.
Source Sinisha
Derived from a drawing in 'The Murmur of the Shells', Samuel Cowen, 1879.
Source Firkin
Remixed from a raster on Pixabay that was uploaded by ArtsyBee.
Source Firkin
Prismatic Groovy Concentric Background 4 No Black
Source GDJ
A grayscale fabric pattern with vertical lines of stitch holes.
Source V. Hartikainen
Design drawn in Paint.net, vectorised using Vector Magic and finished in Inkscape.
Source Firkin
Sort of like the Photoshop transparent background, but better!
Source Alex Parker