A heavy hitter at 400x400px, but lovely still.
Source Breezi
A seamless striped fabric-like texture colored in a dark reddish brown color.
Source V. Hartikainen
A very slick dark rubber grip pattern, sort of like the grip on a camera.
Source Sinisha
Lovely light gray floral motif with some subtle shades.
Source GraphicsWall
Embossed lines and squares with subtle highlights.
Source Alex Parker
Just like your old suit, all striped and smooth.
Source Alex Berkowitz
Used a cherry by doctormo to make this seamless pattern
Source Firkin
Nasty or not, it’s a nice pattern that tiles. Like they all do.
Source Badhon Ebrahim
And some more testing, this time with Seamless Studio. It’s Robots FFS!
Source Seamless Studio
Zero CC tileable moss or lichen covered stone texture, edited from pixabay. CC0
Source Sojan Janso
Bright gray tones with a hint of some metal surface.
Source Hendrik Lammers
A seamless pattern the starting point for which was a 'rainbow twist' texture in Paint.net.
Source Firkin
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
A seamless pattern formed from a tile made from ornament 22. To get the tile, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
A new one called white wall, not by me this time.
Source Yuji Honzawa
Remixed from an image that was uploaded to Pixabay by Pixeline
Source Firkin
Prismatic Abstract Line Art Pattern Background
Source GDJ
A grid of squares with green colours. Since the colours are randomly distributed it is automatically seamless.
Source Firkin
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
Same classic 45-degree pattern, dark version.
Source Luke McDonald
From a drawing in 'Gately's World's Progress', Charles Beale, 1886.
Source Firkin