The unit cell for this seamless pattern can be had in Inkscape by selecting the rectangle and using shift+alt+i
Source Firkin
With a name like this, it has to be hot. Diagonal lines in light shades.
Source Isaac
Same classic 45-degree pattern, dark version.
Source Luke McDonald
Zero CC tileable moss or lichen covered stone texture, edited from pixabay. CC0
Source Sojan Janso
There are quite a few grid patterns, but this one is a super tiny grid with some dust for good measure.
Source Dominik Kiss
Hexagonal dark 3D pattern. What more can you ask for?
Source Norbert Levajsics
A background pattern inspired by designs seen in 'Burghley. The Life of William Cecil', William Charlton, 1857.
Source Firkin
From a drawing in 'Friend or Fortune? The story of a strange year', Robert Overton, 1897.
Source Firkin
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
Here's a subtle marble-like background for use on websites.
Source V. Hartikainen
From a drawing in 'An Old Maid's Love. A Dutch tale told in English', Maarten Maartens, 1891.
Source Firkin
Sharp pixel pattern looking like some sort of fabric.
Source Dmitry
Prismatic Abstract Geometric Background 5 No Black
Source GDJ
Remixed from a drawing in 'Paul's Sister', Frances Peard, 1889.
Source Firkin
Remixed from a raster on Pixabay that was uploaded by ArtsyBee.
Source Firkin
Design drawn in Paint.net, vectorised using Vector Magic and finished in Inkscape.
Source Firkin
A very slick dark rubber grip pattern, sort of like the grip on a camera.
Source Sinisha
New paper pattern with a slightly organic feel to it, using some thin threads.
Source Atle Mo
Remixed from a design on Pixabay. To get the tile this is based on select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
Super simple but very nice indeed. Gray with vertical stripes.
Source Merrin Macleod
Remixed from a drawing in 'The March of Loyalty', Letitia MacClintock, 1884.
Source Firkin
It has waves, so make sure you don’t get sea sickness.
Source CoolPatterns
Run a restaurant blog? Here you go. Done.
Source Andrijana Jarnjak
A nice looking light gray background pattern with diagonal stripes.
Source V. Hartikainen