The unit cell for this seamless pattern can be had in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin
Like the name suggests, this background image consists of a pattern of dark bricks. It may be an option for you, if you are looking for something that looks like a brick wall for use as a background on web pages. It's not a masterpiece, but looks pretty nice when is tiled.
Source V. Hartikainen
Stefan is hard at work, this time with a funky pattern of squares.
Source Stefan Aleksić
A seamless pattern recreated from an image on Pixabay. It is reminiscent of parquet flooring and is formed from a square tile, which can be recovered in Inkscape by selecting the ungrouped rectangle and using shift-alt-I together.
Source Firkin
If you want png files of this u can download them here : viscious-speed.deviantart.com/gallery/27635117
Source Viscious-Speed
The image depicts a Japanese Edo pattern called "kanoko or 鹿の子" meaning "fawn" which has a fur with small white spots.
Source Yamachem
Prismatic Curved Diamond Pattern No Background
Source GDJ
You know, tiny and sharp. I’m sure you’ll find a use for it.
Source Atle Mo
A seamless pattern formed from a sports car on clker.com. To get the tile, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
This is a grid, only it’s noisy. You know. Reminds you of those printed grids you draw on.
Source Vectorpile
Retro Circles Background 8 No Black
Source GDJ
Super subtle indeed, a medium gray pattern with tiny dots in a grid.
Source Designova
No relation to the band, but damn it’s subtle!
Source Thomas Myrman
Fabric-ish patterns are close to my heart. French Stucco to the rescue.
Source Christopher Buecheler
A light gray fabric pattern with faded vertical stripes.
Source V. Hartikainen
A nice and simple gray stucco material. Great on its own, or as a base for a new pattern.
Source Bartosz Kaszubowski