It almost looks a bit blurry, but then again, so are fishes.
Source Petr Šulc
Medium gray pattern with small strokes to give a weave effect.
Source Catherine
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
Prismatic Isometric Cube Wireframe Pattern No Background
Source GDJ
And some more testing, this time with Seamless Studio. It’s Robots FFS!
Source Seamless Studio
Remixed from a drawing in 'Works. Popular edition', John Ruskin, 1886.
Source Firkin
A background pattern inspired by designs seen in 'Burghley. The Life of William Cecil', William Charlton, 1857.
Source Firkin
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
A white version of the very popular linen pattern.
Source Ant Ekşiler
The unit cell for this seamless pattern can be had in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin
The tile this fill pattern is based on can be had by using shift+alt+i on the rectangle.
Source Firkin
From a drawing in 'Bond Slaves. The story of a struggle.', Isabella Varley, 1893.
Source Firkin
Prismatic Hypnotic Pattern No Background
Source GDJ
A seamless pattern drawn originally in Paint.net by distorting a slice of background pattern 116 and copying the resulting triangle numerous times.
Source Firkin
You guessed it – looks a bit like cloth.
Source Peax Webdesign
To get the tile this is based on, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
Pattern that came out of playing with the 'slinky' plug-in for Paint.net
Source Firkin
Prismatic Snowflakes Pattern No Background
Source GDJ
Looks like a technical drawing board: small squares forming a nice grid.
Source We Are Pixel8
This one takes you back to math class. Classic mathematic board underlay.
Source Josh Green
Prismatic Geometric Tessellation Pattern 3 No Background
Source GDJ
Love the style on this one, very fresh. Diagonal diamond pattern. Get it?
Source INS