If you like it a bit trippy, this wave pattern might be for you.
Source Ian Soper
Prismatic Polyskelion Pattern No Background
Source GDJ
A dark metal plate with an embossed grid pattern and a bit of rust. Here's a dark metal plate texture for use as a tiled background on web pages.
Source V. Hartikainen
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
Dark squares with some virus-looking dots in the grid.
Source Hugo Loning
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Pattern #100! A black classic knit-looking pattern.
Source Factorio.us Collective
Abstract Tiled Background Extended 12
Source GDJ
A white version of the very popular linen pattern.
Source Ant Ekşiler
Sounds like something from World of Warcraft. Has to be good.
Source Tony Kinard
A seamless pattern based on a square tile that can be retrieved in Inkscape by selecting the rectangle and using shift-alt-i.
Source Firkin
Drawn in Paint.net and vectorised in Vector Magic.
Source Firkin
Prismatic Triangular Seamless Pattern III With Background
Source GDJ
To get the tile this is based on, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
Prismatic Floral Pattern 3 Variation 3 No Background
Source GDJ
Remixed from a drawing in 'Line and form', Walter Crane, 1914.
Source Firkin
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Looks like a technical drawing board: small squares forming a nice grid.
Source We Are Pixel8
The tile this is based on can be retrieved by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
A cute x, if you need that sort of thing.
Source Juan Scrocchi
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
From a drawing in 'Hubert Montreuil, or the Huguenot and the Dragoon', Francisca Ouvry, 1873.
Source Firkin