Got some felt in my mailbox today, so I scanned it for you to use.
Source Atle Mo
This is the remix of an Openclipart clipart called "Maze" uploaded by "any_ono_mous".Thanks.This is a seamless pattern of a maze.
Source Yamachem
From a drawing in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892.
Source Firkin
Prismatic Floral Pattern 3 Variation 3 No Background
Source GDJ
This is a hot one. Small, sharp and unique.
Source GraphicsWall
Remixed from a raster on Pixabay that was uploaded by ArtsyBee.
Source Firkin
Prismatic Groovy Concentric Background 5 No Black
Source GDJ
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Prismatic Abstract Geometric Background 3
Source GDJ
Light honeycomb pattern made up of the classic hexagon shape.
Source Federica Pelzel
This was formed by distorting an image of a background on Pixabay.
Source Firkin
A seamless pattern that includes the original tile (go to Objects / Pattern / Pattern To Objects in Inkscape's menu to extract it).
Source GDJ
Medium gray fabric pattern with 45-degree lines going across.
Source Atle Mo
Derived from a corner decoration itself found as a jpg on Pixabay.
Source Firkin
Tiny, tiny 3D cubes. Reminds me of the good old pattern from k10k.
Source Etienne Rallion
More bright luxury. This is a bit larger than fancy deboss, and with a bit more noise.
Source Viszt Péter
A fun-looking elastoplast/band-aid pattern. A hint of orange tone in this one.
Source Josh Green
A light background pattern with diagonal stripes. Here's a simple light striped background for you.
Source V. Hartikainen
The green fibers pattern will work very well in grayscale as well.
Source Matteo Di Capua
CC0 and a seamless pattern from a tile drawn in Paint.net .
Source SliverKnight
An interesting dark spotted pattern at an angle.
Source Hendrik Lammers
In the spirit of WWDC 2011, here is a dark iOS inspired linen pattern.
Source Atle Mo
The base gradient edited so now more details are rendered.
Source Lazur URH