To get the tile this is formed from select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Prismatic Polka Dots Mark II 3 No Background
Source GDJ
Sort of like the Photoshop transparent background, but better!
Source Alex Parker
This is a remix of "blue wave-seigaiha".I hope this subtle color version of Seigaiha would be suitable for background .
Source Yamachem
Number 1 in a series of 5 beautiful patterns. Can be found in colors on the submitter’s website.
Source Janos Koos
Bigger is better, right? So here you have some large carbon fiber.
Source Factorio.us Collective
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
This is indeed a bit strange, but here’s to the crazy ones!
Source Christopher Buecheler
A version without colours blended together to give a different look.
Source Firkin
Subtle scratches on a light gray background.
Source Andrey Ovcharov
Prismatic Groovy Concentric Background No Black
Source GDJ
Zero CC tileable hard cover red book, scanned and made by me. CC0
Source Sojan Janso
A seamless pattern formed from background pattern 102
Source Firkin
Looks like a technical drawing board: small squares forming a nice grid.
Source We Are Pixel8
Prismatic Floral Pattern 3 Variation 3 No Background
Source GDJ
A huge one at 800x600px. Made from a photo I took going home after work.
Source Atle Mo
Psychedelic Geometric Background No Black
Source GDJ
Prismatic Geometric Pattern Background
Source GDJ
A repeating background for websites with a texture of black groove stripes.
Source V. Hartikainen
A seamless pattern from a tile drawn in Paint.net and vectorised in Vector Magic
Source Firkin
The name is totally random, but hey, it sounds good.
Source Atle Mo
Seamless pattern formed from a tile that can be extracted by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
Not a pattern for fabrics, but one produced from a jpg of a stack of fabric items that was posted on Pixabay. The tile that this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Prismatic Polka Dots Mark II 3 No Background
Source GDJ
A pattern formed from a squared tile. The tile can be accessed in Inkscape by selecting the rectangle and using shift-alt-i.
Source Firkin
Subtle scratches on a light gray background.
Source Andrey Ovcharov