This one is quite simple in design, it consists of vertical stripes layered on top of a seamless texture.
Source V. Hartikainen
I skipped number 3, because it wasn’t all that great. Sorry.
Source Dima Shiper
Prismatic Groovy Concentric Background 2
Source GDJ
A large pattern with funky shapes and form. An original. Sort of origami-ish.
Source Luuk van Baars
With a name like this, it has to be hot. Diagonal lines in light shades.
Source Isaac
From an image on opengameart.org shared by rubberduck.
Source Firkin
To get the tile this is based on select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
A repeating background of beige (or is it more vanilla yellow) textured stripes. One more background with stripes.
Source V. Hartikainen
A large pattern with funky shapes and form. An original. Sort of origami-ish.
Source Luuk van Baars
Classic vertical lines, in all its subtlety.
Source Cody L
Number 5 in a series of 5 beautiful patterns. Can be found in colors on the submitter’s website.
Source Janos Koos
An orange vertically striped background pattern. Feel free to download and use this orange background pattern, for example, on the web). It resembles a wallpaper with vertical stripes or something similar to it.
Source V. Hartikainen
Design drawn in Paint.net, vectorised using Vector Magic and finished in Inkscape.
Source Firkin
A mid-tone gray pattern with some cement looking texture.
Source Hendrik Lammers
You know you love wood patterns, so here’s one more.
Source Richard Tabor
And some more testing, this time with Seamless Studio. It’s Robots FFS!
Source Seamless Studio
Lovely pattern with splattered vintage speckles.
Source David Pomfret
Made by distorting a simple pattern using the 'sin waves' plugin for Paint.net and vectorising in Vector Magic
Source Firkin