A seamless pattern the unit cell for which can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
Derived from an image that was uploaded to Pixabay by Kaz
Source Firkin
A pale olive green background with a seamless texture.
Source V. Hartikainen
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Remixed from a drawing in 'Chambéry à la fin du XIVe siècle', Timoleon Chapperon, 1863.
Source Firkin
Utilising some flowers from Almeidah. To get the unit tile, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
Smooth Polaroid pattern with a light blue tint.
Source Daniel Beaton
A car pattern?! Can it be subtle? I say yes!
Source Radosław Rzepecki
A seamless pattern with green and yellow diagonal lines on top of a white dotted background.
Source V. Hartikainen
Remixed from a drawing in 'Line and form', Walter Crane, 1914.
Source Firkin
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
You don’t see many mid-tone patterns here, but this one is nice.
Source Joel Klein
A seamless pattern formed from background pattern 102
Source Firkin
A grid of squares with green colours. Since the colours are randomly distributed it is automatically seamless.
Source Firkin
Clean and crisp lines all over the place. Wrap it up with this one.
Source Dax Kieran
Here's a repeatable texture that resembles a light green concrete wall or something similar.
Source V. Hartikainen
High detail stone wall with minor cracks and specks.
Source Projecteightyfive
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
Pattern produced in Paint.net using the Vibrato plug-in.
Source Firkin
All good things come in threes, so I give you the third in my little concrete wall series.
Source Atle Mo