CC0 and a seamless pattern from a tile drawn in Paint.net .
Source SliverKnight
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
A seamless pattern recreated from an image on Pixabay. It is reminiscent of parquet flooring and is formed from a square tile, which can be recovered in Inkscape by selecting the ungrouped rectangle and using shift-alt-I together.
Source Firkin
Love the style on this one, very fresh. Diagonal diamond pattern. Get it?
Source INS
Derived from a JPG that was uploaded to Pixabay by ractapopulous
Source Firkin
First pattern tailor-made for Retina, with many more to come. All the old ones are upscaled, in case you want to re-download.
Source Atle Mo
Remixed from a drawing in 'Prehistoric Man: researches into the origin of civilisation in the old and the new world', Daniel Wilson, 1876.
Source Firkin
A repeating background of beige (or is it more vanilla yellow) textured stripes. One more background with stripes.
Source V. Hartikainen
Prismatic Curved Diamond Pattern No Background
Source GDJ
This makes me wanna shoot some pool! Sweet green pool table pattern.
Source Caveman
CC0 and a seamless pattern from a tile drawn in Paint.net .
Source SliverKnight
I skipped number 3, because it wasn’t all that great. Sorry.
Source Dima Shiper
Design drawn in Paint.net, vectorised using Vector Magic and finished in Inkscape.
Source Firkin
This was formed by distorting an image of a background on Pixabay.
Source Firkin
Clover with background for St. Patrick's Day. Add to a card with a doily, ribbon, a leprechaun or other embellishments.
Source BAJ
Prismatic Polka Dots Mark II No Background
Source GDJ
This one is rather fun and playful. The 2X could be used at 1X too!
Source Welsley
Paper model of a tetrahedron. Modelo de papel de um tetraedro.
Source laobc
From a drawing in 'Gately's World's Progress', Charles Beale, 1886.
Source Firkin
Background formed from the original with an emboss effect
Source GDJ
Not a flat you live inside, like in the UK – but a flat piece of cardboard.
Source Appleshadow
Continuing the geometric trend, here is one more.
Source Mike Warner
A seamless pattern formed from a tile made from page ornament 22. To get the tile, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin