The classic notebook paper with horizontal stripes.
Source Are Sundnes
Small dots with minor circles spread across to form a nice mosaic.
Source John Burks
A seamless pattern the starting point for which was a 'colour modulo' texture in Paint.net.
Source Firkin
Geometric triangles seem to be quite hot these days.
Source Pixeden
Here's a dark background pattern that contains a steel grid pattern as a texture. Use it as a website background or for other purposes. It's free!
Source V. Hartikainen
Remixed from a drawing in 'Kulturgeschichte der Deutschen im Mittelalter' Franz von Loeher, 1891. The unit tile can be had by selecting the rectangle in Inkscape and using shift-alt-i
Source Firkin
Recreated from a pattern found in 'Az Osztrák-Magyar Monarchia irásban és képben', 1882. To get the tile this is based on select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Your eyes can trip a bit from looking at this – use it wisely.
Source Michal Chovanec
Prismatic Hexagonalism Pattern No Background
Source GDJ
Love me some light mesh on a Monday. Sharp.
Source Wilmotte Bastien
Remixed from an image that was uploaded to Pixabay by Pixeline
Source Firkin
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
A seamless pattern formed from background pattern 102
Source Firkin
Wild Oliva or Oliva Wilde? Darker than the others, sort of a medium dark pattern.
Source Badhon Ebrahim
To get the tile this is based on select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
This makes me wanna shoot some pool! Sweet green pool table pattern.
Source Caveman
Prismatic Triangular Background Design Mark II 5
Source GDJ
Greyscale version of a pattern that came out of playing with the 'light rays' plug-in for Paint.net
Source Firkin
Seamless pattern the basic tile for which can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
A seamlessly repeating background pattern of wood. The image is procedurally generated, and, I think, it's turned out quite well.
Source V. Hartikainen