The basic shapes never get old. Simple triangle pattern.
Source Atle Mo
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
To get the tile this is based on, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
A bit like some carbon, or knitted netting if you will.
Source Anna Litvinuk
Prismatic Groovy Concentric Background 4 No Black
Source GDJ
From a drawing in 'Storia del Palazzo Vecchio in Firenze', Aurelio Gotti, 1889.
Source Firkin
A background formed from an image of an old tile on the New York Metropolitan Museum of Art website. To get the base tile, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
Simple combination of stripy squares with their negatively coloured counterparts
Source Firkin
Background Wall, Art Abstract, Block Well & CC0 texture.
Source Ractapopulous
To get the tile this is based on select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
Could remind you a bit of those squares in Super Mario Bros, yeh?
Source Jeff Wall
Remixed from a raster on Pixabay that was uploaded by ArtsyBee.
Source Firkin
Prismatic Groovy Concentric Background 3
Source GDJ
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
Pattern #100! A black classic knit-looking pattern.
Source Factorio.us Collective
Remixed from a raster on Pixabay that was uploaded by ArtsyBee.
Source Firkin