Checkered Light Emboss@2X #281
 Grid  CC BY-SA 3.0

Sort of like the Photoshop transparent background, but better!

Source Alex Parker

 More Textures
Robots@2X #126
 Dark  CC BY-SA 3.0

And some more testing, this time with Seamless Studio. It’s Robots FFS!

Source Seamless Studio

Always Grey@2X #54
 Dark  CC BY-SA 3.0

Crossing lines with a subtle emboss effect on a dark background.

Source Stefan Aleksić

Food and drink design #1897
 Dark  CC 0

Colour version that is close to the original drawing uploaded to Pixabay by pencilparker.

Source Firkin

Decorative divider 283 (version 2) #1855
 Dark  CC 0

Remixed from a drawing in 'In an Enchanted Island', William Mallock, 1892.

Source Firkin