The square tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
This was formed by distorting an image of a background on Pixabay.
Source Firkin
Prismatic Groovy Concentric Background 2
Source GDJ
Colorful Floral Background No Black
Source GDJ
Prismatic Triangular Background Design Mark II 5
Source GDJ
This is a semi-dark pattern, sort of linen-y.
Source Sagive SEO
A heavy dark gray base, some subtle noise and a 45-degree grid makes this look like a pattern with a tactile feel to it.
Source Atle Mo
Bit of a strange name on this one, but still nice. Tiny gray square things.
Source Carlos Valdez
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
There are many carbon patterns, but this one is tiny.
Source Designova
Remixed from a drawing in 'Maidenhood; or, the Verge of the Stream', Laura Jewry, 1876.
Source Firkin
Subtle scratches on a light gray background.
Source Andrey Ovcharov
A rusty grunge background for websites. Feel free to use it in your site's theme.
Source V. Hartikainen
It’s a hole, in a pattern. On your website. Dig it!
Source Josh Green
Has nothing to do with toast, but it’s nice and subtle.
Source Pippin Lee
Prismatic Abstract Geometric Background 5 No Black
Source GDJ
Prepared mostly as a raster in Paint.net and vectorised.
Source Firkin
Pixel by pixel, sharp and clean. Very light pattern with clear lines.
Source M.Ashok
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Old China with a modern twist, take two.
Source Adam Charlts
Classic 45-degree pattern, light version.
Source Luke McDonald
Cubes as far as your eyes can see. You know, because they tile.
Source Jan Meeus