An interesting dark spotted pattern at an angle.
Source Hendrik Lammers
It has waves, so make sure you don’t get sea sickness.
Source CoolPatterns
Sharp diamond pattern. A small 24x18px tile.
Source Tom Neal
Lovely pattern with splattered vintage speckles.
Source David Pomfret
CC0 and seamless wellington boot pattern.
Source SliverKnight
Here's a brown background pattern with subtle stripes. I hope you'll like the color. If not, feel free to change it using an image editor, if you know how of course. Personally, I'm using GIMP to create these backgrounds.
Source V. Hartikainen
Just like your old suit, all striped and smooth.
Source Alex Berkowitz
Seamless pattern formed from a tile that can be had by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
Beautiful dark noise pattern with some dust and grunge.
Source Vincent Klaiber
High detail stone wall with minor cracks and specks.
Source Projecteightyfive
A huge one at 800x600px. Made from a photo I took going home after work.
Source Atle Mo