A seamless pattern the unit cell for which can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
Prismatic Geometric Pattern Background 2 No Black
Source GDJ
A seamless pattern with green and yellow diagonal lines on top of a white dotted background.
Source V. Hartikainen
The tile for this is based on a repeating unit close to a design on Pixabay. It can be had by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
Don’t look at this one too long if you’re high on something.
Source Luuk van Baars
The classic subtle pattern. Sort of wall/brick looking. Or moon-looking?
Source Joel Klein
Prismatic Polka Dots Mark II 2 No Background
Source GDJ
This is a hot one. Small, sharp and unique.
Source GraphicsWall
Prismatic Groovy Concentric Background No Black
Source GDJ
Number 5 in a series of 5 beautiful patterns. Can be found in colors on the submitter’s website.
Source Janos Koos
A background pattern inspired by designs seen in 'Burghley. The Life of William Cecil', William Charlton, 1857.
Source Firkin
No relation to the band, but damn it’s subtle!
Source Thomas Myrman
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
Sharp diamond pattern. A small 24x18px tile.
Source Tom Neal
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
Continuing the geometric trend, here is one more.
Source Mike Warner
I’m not going to lie – if you submit something with the words Norwegian and Rose in it, it’s likely I’ll publish it.
Source Fredrik Scheide
An emulated “transparent” background pattern, like that of all kinds of computer graphics software.
Source AdamStanislav
Looks like a technical drawing board: small squares forming a nice grid.
Source We Are Pixel8
Prismatic Groovy Concentric Background 3 No Black
Source GDJ
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
This one is something special. I’d call it a flat pattern, too. Very well done, sir!
Source GetDiscount
A dark gray, sandy pattern with small light dots, and some angled strokes.
Source Atle Mo
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
Smooth Polaroid pattern with a light blue tint.
Source Daniel Beaton