A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
A black tile-able background with paper-like texture.
Source V. Hartikainen
Vector version of a png that was uploaded to Pixabay by pencilparker
Source Firkin
Everyone needs some stardust. Sprinkle it on your next project.
Source Atle Mo
Derived from an image that was uploaded to Pixabay by TheDigitalArtist
Source Firkin
Retro Circles Background 5 No Black
Source GDJ
From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Prismatic Snowflakes Pattern No Background
Source GDJ
Drawn in Paint.net and vectorised in Vector Magic.
Source Firkin
Got some felt in my mailbox today, so I scanned it for you to use.
Source Atle Mo
A background pattern with wavy green vertical stripes. This one has green stripes on a white background. Download if you like it.
Source V. Hartikainen
Detailed but still subtle and quite original. Lovely gray shades.
Source Kim Ruddock