CC0 and a seamless pattern from a tile drawn in Paint.net .
Source SliverKnight
Three shades of gray makes this pattern look like a small carbon fiber surface. Great readability even for small fonts.
Source Atle Mo
Prismatic Groovy Concentric Background 4 No Black
Source GDJ
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
Made by distorting a simple pattern using the 'sin waves' plugin for Paint.net and vectorising in Vector Magic
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
Subtle scratches on a light gray background.
Source Andrey Ovcharov
Design drawn in Paint.net, vectorised using Vector Magic and finished in Inkscape.
Source Firkin
Used a cherry by doctormo to make this seamless pattern
Source Firkin
This is indeed a bit strange, but here’s to the crazy ones!
Source Christopher Buecheler
Derived from a JPG that was uploaded to Pixabay by ractapopulous
Source Firkin
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
A cute x, if you need that sort of thing.
Source Juan Scrocchi
Number five from the same submitter, makes my job easy.
Source Dima Shiper
A rusty grunge background for websites. Feel free to use it in your site's theme.
Source V. Hartikainen
You guessed it – looks a bit like cloth.
Source Peax Webdesign
You know I love paper patterns. Here is one from Stephen. Say thank you!
Source Stephen Gilbert
Background pattern originally a PNG drawn in Paint.net
Source Firkin
You don’t see many mid-tone patterns here, but this one is nice.
Source Joel Klein