Dark pattern with some nice diagonal stitched lines crossing over.
Source Ashton
Seamless pattern made from a tile that can be obtained in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin
Remixed from a design seen on Pixabay. The basic tile can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Could be paper, could be a Polaroid frame – up to you!
Source Chaos
Abstract Tiled Background Extended 12
Source GDJ
Not so subtle. These tileable wood patterns are very useful.
Source Elemis
This was formed by distorting an image of a background on Pixabay.
Source Firkin
U.S.-based National Fire Protection Association standard fire diamond for flagging risks posed by hazardous materials. The red diamond has a number 0-4 depending on flammability. The blue diamond has a number 0-4 depending on health hazard. The yellow has a number 0-4 depending on reactivity. the white square has a special notice, e.g OX for oxidizer.
Source Firkin
A seamless pattern the unit cell for which can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
A dark metallic background with a pattern of stamped dots. Here's a dark "metallic" background pattern for you.
Source V. Hartikainen
Sharp but soft triangles in light shades of gray.
Source Pixeden
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
Prismatic Hypnotic Pattern 2 No Background
Source GDJ
This one is something special. I’d call it a flat pattern, too. Very well done, sir!
Source GetDiscount
A seamless texture of worn out "cardboard".
Source V. Hartikainen
A playful triangle pattern with different shades of gray.
Source Dimitrie Hoekstra
Design drawn in Paint.net, vectorised using Vector Magic and finished in Inkscape.
Source Firkin
Remixed from a design seen on Pixabay. The basic tile can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
This one takes you back to math class. Classic mathematic board underlay.
Source Josh Green
Recreated from a pattern found in 'Az Osztrák-Magyar Monarchia irásban és képben', 1882. To get the tile this is based on select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
If you like it a bit trippy, this wave pattern might be for you.
Source Ian Soper
From a drawing in 'In an Enchanted Island', William Mallock, 1892.
Source Firkin