A huge one at 800x600px. Made from a photo I took going home after work.
Source Atle Mo
A free seamless background image with abstract texture of green "curtain".
Source V. Hartikainen
Light gray version of the Binding pattern that looks a bit like fabric.
Source Newbury
Dark, lines, noise, tactile. You get the drift.
Source Anatoli Nicolae
To get the tile this is based on, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
Prismatic Groovy Concentric Background 2 No Black
Source GDJ
Small gradient crosses inside 45-degree boxes, or bigger crosses if you will.
Source Wassim
To get the tile this is based on, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
Prismatic Abstract Background Design No Black
Source GDJ
This one is rather fun and playful. The 2X could be used at 1X too!
Source Welsley
Vertical lines with a bumpy, yet crisp, feel to it.
Source Raasa
Submitted as a black pattern, I made it light and a few steps more subtle.
Source Andy
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
A seamless pattern based on a square tile that can be retrieved in Inkscape by selecting the rectangle and using shift-alt-i.
Source Firkin
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
Zero CC tileable yellow craft paper; scanned and made by me. CC0
Source Sojan Janso
Same as the black version, but now in shades of gray. Very subtle and fine grained.
Source Atle Mo
From a drawing in 'Line and form', Walter Crane, 1914.
Source Firkin
The image depicts a seamless pattern of a tortoise in tortoiseshell (hexagon).
Source Yamachem