A seamless pattern the unit cell for which can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
I love these crisp, tiny, super subtle patterns.
Source Badhon Ebrahim
A dark brown fabric-like background texture with seamless pattern of winding stripes.
Source V. Hartikainen
Prismatic Groovy Concentric Background 2
Source GDJ
Everyone needs some stardust. Sprinkle it on your next project.
Source Atle Mo
A simple circle. That’s all it takes. This one is even transparent, for those who like that.
Source Saqib
Utilising some flowers from Almeidah. To get the unit tile, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
Embossed lines and squares with subtle highlights.
Source Alex Parker
A good starting point for a cardboard pattern. This would work well in a variety of colors.
Source Atle Mo
Cubes as far as your eyes can see. You know, because they tile.
Source Jan Meeus
A seamless pattern drawn originally in Paint.net by distorting a slice of background pattern 116 and copying the resulting triangle numerous times.
Source Firkin
The tile can be had by using shift+alt+i on the selected rectangle in Inkscape
Source Firkin
A seamless pattern created from a square tile. To get the tile, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
A white version of the very popular linen pattern.
Source Ant Ekşiler
You may use it as is, or modify it as you like.
Source V. Hartikainen
Abstract Stars Geometric Pattern Prismatic No Background
Source GDJ
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
Smooth Polaroid pattern with a light blue tint.
Source Daniel Beaton
Brushed aluminum, in a bright gray version. Lovely 2X as well.
Source Andre Schouten
A car pattern?! Can it be subtle? I say yes!
Source Radosław Rzepecki
Abstract Tiled Background Extended 6
Source GDJ
Here's an yet another seamless note paper texture for use as a background on websites.
Source V. Hartikainen
Bumps, highlight and shadows – all good things.
Source Badhon Ebrahim