Derived from an image that was uploaded to Pixabay by TheDigitalArtist
Source Firkin
A very dark spotted twinkle pattern for your twinkle needs.
Source Badhon Ebrahim
There are many carbon patterns, but this one is tiny.
Source Designova
A pattern derived from repeating unit cells each derived from part of a fractal rendering in paint.net.
Source Firkin
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
The image depicts a seamless pattern made using a bird's face.
Source Yamachem
Prismatic Geometric Tessellation Pattern 2 No Background
Source GDJ
Alternative colour scheme. 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
A dark pattern made out of 3×3 circles and a 1px shadow. This works well as a carbon texture or background.
Source Atle Mo
Simple gray checkered lines, in light tones.
Source Radosław Rzepecki
You don’t see many mid-tone patterns here, but this one is nice.
Source Joel Klein
This ladies and gentlemen, is texturetastic! Love it.
Source Adam Pickering
A bit of scratched up grayness. Always good.
Source Dmitry