A seamless pattern the unit cell for which can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
A seamless background pattern with impressed gray dots.
Source V. Hartikainen
Smooth Polaroid pattern with a light blue tint.
Source Daniel Beaton
Floral patterns will never go out of style, so enjoy this one.
Source Lasma
An abstract texture of black metal pipes (seamless).
Source V. Hartikainen
Love the style on this one, very fresh. Diagonal diamond pattern. Get it?
Source INS
Derived from an image that was uploaded to Pixabay by mdmelo.
Source Firkin
Here is a new seamless wood texture for using as blog or website backgrounds.
Source V. Hartikainen