A good starting point for a cardboard pattern. This would work well in a variety of colors.
Source Atle Mo
Derived from a PNG that was uploaded to Pixabay by nutkitten
Source Firkin
A dark one with geometric shapes and dotted lines.
Source Mohawk Studios
Background formed from the original with an emboss effect.
Source Firkin
From a drawing in 'The Quiver of Love', Walter Crane, 1876
Source Firkin
emixed from a JPG that was uploaded to Pixabay by Kyotime
Source Firkin
You know you love wood patterns, so here’s one more.
Source Richard Tabor
Derived from a drawing in 'Elfrica. An historical romance of the twelfth century', Charlotte Boger, 1885
Source Firkin
And some more testing, this time with Seamless Studio. It’s Robots FFS!
Source Seamless Studio
Dare I call this a «flat pattern»? Probably not.
Source Dax Kieran
You just can’t get enough of the fabric patterns, so here is one more for your collection.
Source Krisp Designs
Just to prove my point, here is a slightly modified dark version.
Source Atle Mo
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
From a drawing in 'The Quiver of Love', Walter Crane, 1876
Source Firkin
Remixed from a drawing in 'Analecta Eboracensia', Thomas Widdrington, 1897.
Source Firkin
From a drawing in 'A Life Interest', Mrs Alexander, 1888.
Source Firkin
Sharp but soft triangles in light shades of gray.
Source Pixeden
One of the few full-color patterns here, but this one was just too good to pass up.
Source Alexey Usoltsev
Prismatic Polka Dots Mark II 3 No Background
Source GDJ
This is the remix of "Tileable Wave Pattern 2" uploaded by "Arvin61r58".Thanks.I added a wire-mesh fence seamless pattern as a lower layer.
Source Yamachem
To get the tile this is based on select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Fabric-ish patterns are close to my heart. French Stucco to the rescue.
Source Christopher Buecheler
Prismatic Hypnotic Pattern No Background
Source GDJ
From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
The perfect pattern for all your blogs about type, or type-related matters.
Source Atle Mo
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
The tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
A set of paper filters. The base texture is generated the same way, only the compositing mode is varied.
Source Lazur URH