Background pattern 225 (colour 2) #2326
 Yellow  CC 0

Seamless pattern formed from a tile that can be extracted by selecting the rectangle in Inkscape and using shift-alt-i.

Source Firkin

 More Textures
Darth Stripe #99
 Dark  CC BY-SA 3.0

Diagonal lines with a lot of texture to them.

Source Ashton

Polonez Pattern@2X #335
 Gray  CC BY-SA 3.0

A car pattern?! Can it be subtle? I say yes!

Source Radosław Rzepecki

Retro Squares Background@2X #415
 Noise  CC 0

Retro Squares Background

Source GDJ

Background pattern 8 (colour) #211
 Noise  CC 0

Colour version of a pattern that came out of playing with the 'light rays' plug-in for Paint.net

Source Firkin

Fish Pattern Background #233
 Noise  CC 0

From PDP.

Source GDJ

MBossed #193
 Grid  CC BY-SA 3.0

Embossed lines and squares with subtle highlights.

Source Alex Parker

Colorful Floral Background 3 #483
 Dark  CC 0

Colorful Floral Background 3

Source GDJ

Brushed Alum Dark@2X #66
 Dark  CC BY-SA 3.0

Because I love dark patterns, here is Brushed Alum in a dark coating.

Source Tim Ward

Background pattern 259 #2133
 Red  CC 0

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

Soft Kill #318
 Dark  CC BY-SA 3.0

Pattern #100! A black classic knit-looking pattern.

Source Factorio.us Collective

Geometric pattern #2006
 Grid  CC 0

A monochrome pattern from a tile that can be had by selecting the rectangle in Inkscaope and using shift+alt+i

Source Firkin

Foggy Birds@2X #580
 Light  CC BY-SA 3.0

Hey, you never know when you’ll need a bird pattern, right?

Source Pete Fecteau