Polonez Pattern #334
 Gray  CC BY-SA 3.0

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

Source Radosław Rzepecki

 More Textures
Pinstripe #35
 Light  CC BY-SA 3.0

Light gray pattern with a thin pinstripe.

Source Brandon

Vintage pattern 2 #2295
 Yellow  CC 0

Inspired by a pattern seen on a public domain image of a very old tile. To get the unit cell, select the rectangle in Inkscape and use shift+alt+i.

Source Firkin

Prismatic Groovy Concentric Background No Black #451
 Noise  CC 0

Prismatic Groovy Concentric Background No Black

Source GDJ

Diamond pattern 2 (colour 4) #2265
 Red  CC 0

From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.

Source Firkin

Iron Grip #587
 Dark  CC BY-SA 3.0

Sounds like something from World of Warcraft. Has to be good.

Source Tony Kinard

Prismatic Isometric Cube Wireframe Pattern No Background@2X #500
 Light  CC 0

Prismatic Isometric Cube Wireframe Pattern No Background

Source GDJ

Carbon Fiber v2 #105
 Carbon  CC BY-SA 3.0

One more updated pattern. Not really carbon fiber, but it’s the most popular pattern, so I’ll give you an extra choice.

Source Atle Mo

Background pattern 306 (colour 2) #1881
 Colorful  CC 0

Seamless pattern the tile for which can be had by using shift-alt-I on the selected rectangle in Inkscape.

Source Firkin

Background pattern 232 #2297
 Dark  CC 0

Heavily remixed from a drawing in 'Barbara Leybourne; a story of eighty years ago', Sarah Hamer, 1889.

Source Firkin

Floral background 5 #2404
 Fabric  CC 0

A seamless pattern formed from a square tile. The tile can be retrieved by selecting the rectangle in Inkscape and using shift-alt-I.

Source Firkin