More Textures
Bright Squares@2X #88
 Light  CC BY-SA 3.0

It’s okay to be square! A nice light gray pattern with random squares.

Source Waseem Dahman

Polonez Pattern #334
 Gray  CC BY-SA 3.0

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

Source Radosław Rzepecki

Carbon Fiber Big #326
 Carbon  CC BY-SA 3.0

Bigger is better, right? So here you have some large carbon fiber.

Source Factorio.us Collective

Diamond pattern (colour 4) #2282
 Blue  CC 0

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

Source Firkin

Background pattern 250 (colour) #2171
 Yellow  CC 0

To get the tile this is based on select the rectangle in Inkscape and use shift+alt+i.

Source Firkin

Connected #348
 Light  CC BY-SA 3.0

White circles connecting on a light gray background.

Source Mark Collins

Background pattern pink #1948
 Pink  CC 0

To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.

Source Firkin

Noisy #45
 Paper  CC BY-SA 3.0

Looks a bit like concrete with subtle specks spread around the pattern.

Source Mladjan Antic

Paper texture filter #149
 Paper  CC 0

Filter simulating the texture of heavy paper.

Source Kelan

Little Pluses #73
 Light  CC BY-SA 3.0

Subtle grunge and many little pluses on top.

Source Atle Mo

Retro Squares Background 4 #418
 Dark  CC 0

Retro Squares Background 4

Source GDJ

Prismatic Hexagonalism Pattern No Background #391
 Light  CC 0

Prismatic Hexagonalism Pattern No Background

Source GDJ

Mirrored Squares@2X #124
 Dark  CC BY-SA 3.0

Did some testing with Repper Pro tonight, and this gray mid-tone pattern came out.

Source Atle Mo