More Textures
Cardboard@2X #279
 Paper  CC BY-SA 3.0

A good starting point for a cardboard pattern. This would work well in a variety of colors.

Source Atle Mo

Colorful Stripes Background #400
 Noise  CC 0

Colorful Stripes Background

Source GDJ

Prismatic Polka Dots Mark II No Background #530
 Noise  CC 0

Prismatic Polka Dots Mark II No Background

Source GDJ

Elegant Grid@2X #317
 Wall  CC BY-SA 3.0

This is a hot one. Small, sharp and unique.

Source GraphicsWall

Ravenna #354
 Wall  CC BY-SA 3.0

I guess this is inspired by the city of Ravenna in Italy and its stone walls.

Source Sentel

Rocky Wall@2X #42
 Light  CC BY-SA 3.0

High detail stone wall with minor cracks and specks.

Source Projecteightyfive

Background pattern 238 (colour 2) #2228
 Green  CC 0

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

Source Firkin

Background pattern 230 (colour 3) #2303
 Green  CC 0

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

Source Firkin

Prismatic Curved Diamond Pattern 3 No Background@2X #540
 Diamond  CC 0

Prismatic Curved Diamond Pattern 3 No Background

Source GDJ

Background pattern 252 (colour 3) #2160
 Green  CC 0

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

Background pattern 256 #2139
 Red  CC 0

Remixed from a design on Pixabay. To get the tile this is based on select the rectangle in Inkscape and use shift-alt-i

Source Firkin

Batthern #324
 Grid  CC BY-SA 3.0

Sometimes simple really is what you need, and this could fit you well.

Source Factorio.us Collective

Dark Stripes@2X #40
 Dark  CC BY-SA 3.0

Very dark pattern with some noise and 45-degree lines.

Source Stefan Aleksić

Spirals pattern #1994
 Colorful  CC 0

Uses spirals from Pixabay. To get the basic tile select the rectangle in Inkscape and use shift+alt+i

Source Firkin

Background pattern 202 (colour 2) #2489
 Green  CC 0

Based on several public domain drawings on Wikimedia Commons. This was formed from a rectangular tile. The tile can be accessed in Inkscape by selecting the rectangle and using shift-alt-i

Source Firkin