From a drawing in 'The Quiver of Love', Walter Crane, 1876
Source Firkin
Sort of like the Photoshop transparent background, but better!
Source Alex Parker
Prismatic Curved Diamond Pattern 6 No Background
Source GDJ
Sometimes simple really is what you need, and this could fit you well.
Source Factorio.us Collective
A nice looking light gray background pattern with diagonal stripes.
Source V. Hartikainen
From a drawing in 'Friend or Fortune? The story of a strange year', Robert Overton, 1897.
Source Firkin
To get the tile this is based on select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
You can never get enough of these tiny pixel patterns with sharp lines.
Source Designova
Not sure if this is related to the Nami you get in Google image search, but hey, it’s nice!
Source Dertig Media
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
CC0 and a seamless pattern from a tile drawn in Paint.net .
Source SliverKnight
After 1 comes 2, same but different. You get the idea.
Source Hendrik Lammers
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
A seamless background of warped stripes on paper.
Source V. Hartikainen
This yellow background consists of a pattern of glossy gold buttons arranged in polka dot style on a seamless texture. Here's a pale yellow background pattern. Feel free to use it for your needs!
Source V. Hartikainen
Super detailed 16×16 tile that forms a beautiful pattern of straws.
Source Pavel
Adapted heavily from a JPG that was uploaded to Pixabay by Viscious-Speed.
Source Firkin
Sort of like the Photoshop transparent background, but better!
Source Alex Parker
A fun-looking elastoplast/band-aid pattern. A hint of orange tone in this one.
Source Josh Green
Black brick wall pattern. Brick your site up!
Source Alex Parker
The file was named striped lens, but hey – Translucent Fibres works too.
Source Angelica
A seamless pattern formed from a square tile. The tile can be retrieved by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
A light brushed aluminum pattern for your pleasure.
Source Tim Ward
Prismatic Abstract Line Art Pattern Background 2
Source GDJ