A seamless pattern based on a rectangular tile that can be retrieved in Inkscape by selecting the rectangle and using shift-alt-i.
Source Firkin
Real snow that tiles, not easy. This is not perfect, but an attempt.
Source Atle Mo
The edges of all the red objects line up either vertically or horizontally, but it doesn't appear so. Made from a square tile that can be got by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
ZeroCC tileable mossy (lichen) stone texture, edited from pixabay. CC0
Source Sojan Janso
Background Wall, Art Abstract, Blue Well & CC0 texture.
Source Ractapopulous
The image depicts a seamless pattern of pine tree leaves.
Source Yamachem
Sharp pixel pattern looking like some sort of fabric.
Source Dmitry
Brushed aluminum, in a bright gray version. Lovely 2X as well.
Source Andre Schouten
To get the tile this is based on, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
A black tile-able background with paper-like texture.
Source V. Hartikainen
A repeating gloomy background image. This one consists of a pattern of black chains layered on top of a dark textured background.
Source V. Hartikainen
More in the paper realm, this time with fibers.
Source Jorge Fuentes
A seamless background drawn in Paint.net and vectorised with Vector Magic. The starting point was a photograph of drinking straws from Pixabay.
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
Seamless Dark Grunge Texture. Here's a new grunge texture for use as a background.
Source V. Hartikainen
A nice one indeed, but I have a feeling we have it already? If you spot a copy, let me know on Twitter.
Source Graphiste
A huge one at 800x600px. Made from a photo I took going home after work.
Source Atle Mo
This one is amazing, truly original. Go use it!
Source Viahorizon
Remixed from a drawing in 'Chambéry à la fin du XIVe siècle', Timoleon Chapperon, 1863.
Source Firkin
From a drawing in 'Friend or Fortune? The story of a strange year', Robert Overton, 1897.
Source Firkin
This was formed by distorting an image of a background on Pixabay.
Source Firkin
From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Actually remixed from a pattern on Pixabay. But then noticed a very similar one on Openclipart.org uploaded by btj51q2.
Source Firkin
Remixed from a drawing that was uploaded to Pixabay by captenpub.
Source Firkin