Retro Circles Background 4 No Black
Source GDJ
The unit cell for this seamless pattern can be had in Inkscape by selecting the rectangle and using shift+alt+i
Source Firkin
Prismatic Polyskelion Pattern No Background
Source GDJ
You don’t see many mid-tone patterns here, but this one is nice.
Source Joel Klein
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
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
Prismatic Polka Dots Mark II 3 No Background
Source GDJ
This is the third pattern called Dark Denim, but hey, we all love them!
Source Brandon Jacoby
Nice and simple crossed lines in dark gray tones.
Source Stefan Aleksić
A background pattern with a look of rough fabric.
Source V. Hartikainen
Prismatic Rounded Squares Grid 4 No Background
Source GDJ
Number 2 in a series of 5 beautiful patterns. Can be found in colors on the submitter’s website.
Source Janos Koos
Abstract Stars Geometric Pattern Prismatic No Background
Source GDJ
Formed by distorting a JPG from PublicDomainPictures
Source Firkin
Got some felt in my mailbox today, so I scanned it for you to use.
Source Atle Mo
This one could be the shirt of a golf player. Angled lines in different thicknesses.
Source Olivier Pineda
This was formed by distorting an image of a background on Pixabay.
Source Firkin
A free seamless background image with abstract texture of green "curtain".
Source V. Hartikainen
Super detailed 16×16 tile that forms a beautiful pattern of straws.
Source Pavel
There are quite a few grid patterns, but this one is a super tiny grid with some dust for good measure.
Source Dominik Kiss
A seamless chequerboard pattern formed from a tile that can be had in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin