You can never get enough of these tiny pixel patterns with sharp lines.
Source Designova
A seamless pattern the unit cell for which can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
The image is a design of blue glass.How about using it as background image?
Source Yamachem
Prismatic Basic Pattern 2 No Background
Source GDJ
Vertical lines with a bumpy, yet crisp, feel to it.
Source Raasa
To get the tile this is based on, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
Nicely crafted paper pattern, although a bit on the large side (500x593px).
Source Blaq Annabiosis
If you want png files of this u can download them here : viscious-speed.deviantart.com/gallery/27635117
Source Viscious-Speed
A pattern derived from repeating unit cells each derived from part of a fractal rendering in paint.net.
Source Firkin
CC0 and a seamless pattern from a tile drawn in Paint.net .
Source SliverKnight
Because I love dark patterns, here is Brushed Alum in a dark coating.
Source Tim Ward
From a drawing in 'Hyde Park from Domesday-Book to date', John Ashton, 1896.
Source Firkin
A pale orange background pattern with glossy groove stripes.
Source V. Hartikainen
Remixed from a drawing in 'The March of Loyalty', Letitia MacClintock, 1884.
Source Firkin
If you want png files of thisu can download them here :
Source Viscious-Speed
Prismatic Abstract Geometric Background 5 No Black
Source GDJ
Found on the ground in french cafe in kunming, Yunnan, china
Source Rejon
Prismatic Hypnotic Pattern 2 No Background
Source GDJ
A monochrome pattern from a tile that can be had by selecting the rectangle in Inkscaope and using shift+alt+i
Source Firkin