Square design drawn in Paint.net and vectorized in Vector Magic.
Source Firkin
I skipped number 3, because it wasn’t all that great. Sorry.
Source Dima Shiper
Adapted from an image that was uploaded to Pixabay by Anerma.
Source Firkin
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Remixed from a raster on Pixabay, that was uploaded by ArtsyBee.
Source Firkin
Seamless pattern the tile for which can be had by using shift-alt-I on the selected rectangle in Inkscape.
Source Firkin
You know, tiny and sharp. I’m sure you’ll find a use for it.
Source Atle Mo
The image depicts meshed silhouettes of various things.The original image is an OCAL clipart called "Enter FOSSASIA 2016 #IoT T-shirt Design Contest" uploaded by "openclipart".Thanks.
Source Yamachem
A pale olive green background with a seamless texture.
Source V. Hartikainen
People seem to enjoy dark patterns, so here is one with some circles.
Source Atle Mo
Prismatic Curved Diamond Pattern 2 No Background
Source GDJ
This could be a hippy vintage wallpaper.
Source Tileable Patterns
Luxury pattern, looking like it came right out of Paris.
Source Daniel Beaton
Light and tiny, just the way you like it.
Source Rohit Arun Rao
Prismatic Abstract Background Design No Black
Source GDJ
This is the remix of "Colorful Floral Pattern Background 3" uploaded by "GDJ". Thanks.
Source Yamachem
A free background tile with a pattern of pink bump dots. This background tile is sweet! Moreover, it's designed for use as website backgrounds.
Source V. Hartikainen
This one is quite simple in design, it consists of vertical stripes layered on top of a seamless texture.
Source V. Hartikainen
Not a flat you live inside, like in the UK – but a flat piece of cardboard.
Source Appleshadow
The original enhanced with one of Inkscapes's filters.
Source Firkin
Prismatic Groovy Concentric Background No Black
Source GDJ
Light square grid pattern, great for a “DIY projects” sort of website, maybe?
Source Rafael Almeida
This was formed by distorting an image of a background on Pixabay.
Source Firkin