Dark squares with some virus-looking dots in the grid.
Source Hugo Loning
A seamless pale yellow paper background with a pattern of animal tracks.
Source V. Hartikainen
f you want png files of this u can download them here : viscious-speed.deviantart.com/gallery/27635117
Source Viscious-Speed
From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
This is a seamless pattern of a woody texture.The original image is here:https://pixabay.com/ja/users/ClassicallyPrinted-1302233/
Source Yamachem
Here's a tile-able wood background image for use in web design.
Source V. Hartikainen
I know there is one here already, but this is sexy!
Source Gjermund Gustavsen
So tiny, just 7 by 7 pixels – but still so sexy. Ah yes.
Source Dmitriy Prodchenko
CC0 and a seamless pattern from a tile drawn in Paint.net .
Source SliverKnight
ZeroCC tileable stone texture, edited from pixabay, CC0
Source Sojan Janso
Like the name says, light and gray, with some small dots and circles.
Source Brenda Lay
A seamless background tile of aged paper with shabby look.
Source V. Hartikainen
Here is a new seamless wood texture for using as blog or website backgrounds.
Source V. Hartikainen