Got some felt in my mailbox today, so I scanned it for you to use.
Source Atle Mo
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
Prismatic Polka Dots Mark II 2 No Background
Source GDJ
Seamless Olive Green Web Background Image
Source V. Hartikainen
A seamless pattern drawn originally in Paint.net by distorting a slice of background pattern 116 and copying the resulting triangle numerous times.
Source Firkin
Looks like a technical drawing board: small squares forming a nice grid.
Source We Are Pixel8
Zero CC tileable grass texture, photographed and made by me. CC0
Source Sojan Janso
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Adapted heavily from a JPG that was uploaded to Pixabay by Viscious-Speed.
Source Firkin
Prismatic Floral Background No Black
Source GDJ
Remixed from a drawing in 'Works. Popular edition', John Ruskin, 1886.
Source Firkin
Prismatic Abstract Geometric Background 5
Source GDJ
Alternative colour scheme for the original floral pattern.
Source Firkin
A set of paper filters. The base texture is generated the same way, only the compositing mode is varied.
Source Lazur URH
That’s what it is, a dark dot. Or sort of carbon looking.
Source Tsvetelin Nikolov
Prismatic Curved Diamond Pattern 6 No Background
Source GDJ
Seamless pattern formed from a square tile that can be retrieved in Inkscape by selecting the rectangle and using shift-alt-i.
Source Firkin