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

 More Textures
Background pattern yellow #1999
 Yellow  CC 0

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

Source Firkin

Dark Denim 3@2X #596
 Dark  CC BY-SA 3.0

This is the third pattern called Dark Denim, but hey, we all love them!

Source Brandon Jacoby

Nami@2X #576
 Dark  CC BY-SA 3.0

Not sure if this is related to the Nami you get in Google image search, but hey, it’s nice!

Source Dertig Media

Background pattern 239 #2217
 Red  CC 0

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

Source Firkin

Background2@2X #477
 Wall  CC 0

rug texture background

Source Jilllio

Background pattern 328 (colour 2) #1800
 Green  CC 0

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

Source Firkin

wire-mesh fence seamless pattern #2492
 Grid  CC 0

The image a seamless pattern of a wire-mesh fence.I want you to use this pattern as a lower layer.

Source Yamachem

Exclusive Paper@2X #24
 Light  CC BY-SA 3.0

Paper pattern with small dust particles and 45-degree strokes.

Source Atle Mo

Decorative divider 252 #2065
 Dark  CC 0

Remix from a drawing in 'Ostatnie chwile powstania styczniowego', Zygmunt Sulima, 1887.

Source Firkin