Super simple but very nice indeed. Gray with vertical stripes.
Source Merrin Macleod
A seamless pattern from a tile drawn in Paint.net and vectorised in Vector Magic
Source Firkin
Inspired by a pattern found in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892.
Source Firkin
Seamless pattern the tile for which can be had by using shift-alt-I on the selected rectangle in Inkscape.
Source Firkin
From a drawing in 'Two Women in the Klondike', Mary Hitchcock, 1899.
Source Firkin
A smooth mid-tone gray, or low contrast if you will, linen pattern.
Source Jordan Pittman
Inspired by an image that was uploaded to Pixabay by geralt
Source Firkin
This seamless light brown background texture resembles a wallpaper with vertical stripes. One way to use it is as a tiled background on web sites.
Source V. Hartikainen
The square tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
And some more testing, this time with Seamless Studio. It’s Robots FFS!
Source Seamless Studio
Remixed from a design seen on Pixabay. The basic tile can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
Your eyes can trip a bit from looking at this – use it wisely.
Source Michal Chovanec
Background formed from the original with an emboss effect
Source GDJ
Prismatic Polka Dots Mark II 3 No Background
Source GDJ
Here's a seamless brown cork board background texture. Feel free to download or reshare if you like.
Source V. Hartikainen
Don’t look at this one too long if you’re high on something.
Source Luuk van Baars
It looks like a polished stone surface to me. Download it for free, as always.
Source V. Hartikainen
A background tile of dark textile. Made this a long time ago and just now decided to publish it.
Source V. Hartikainen