Tessellation 14 variant 1 #2530
 Grid  CC 0

A seamless pattern formed from a modified version of rwwgub's tile. To get the tile, select the rectangle in Inkscape and use shift+alt+i.

Source Firkin

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

Sort of like the Photoshop transparent background, but better!

Source Alex Parker

Prismatic Curved Diamond Pattern No Background@2X #537
 Diamond  CC 0

Prismatic Curved Diamond Pattern No Background

Source GDJ

My Little Plaid #332
 Light  CC BY-SA 3.0

Repeating squares overlapping.

Source Pete Fecteau

Soft Kill@2X #319
 Dark  CC BY-SA 3.0

Pattern #100! A black classic knit-looking pattern.

Source Factorio.us Collective

Prismatic Geometric Pattern Background 2 #409
 Noise  CC 0

Prismatic Geometric Pattern Background 2

Source GDJ

Background pattern 224 (colour 2) #2341
 Colorful  CC 0

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

Source Firkin

"Black Chains", Gloomy Background #1082
 Metal  CC BY-SA 3.0

A repeating gloomy background image. This one consists of a pattern of black chains layered on top of a dark textured background.

Source V. Hartikainen

Prismatic Dots Background 7@2X #514
 Dark  CC 0

Prismatic Dots Background 7

Source GDJ

Background pattern 105 #563
 Dark  CC 0

A seamless pattern formed from background pattern 102

Source Firkin

Abstract Stars Geometric Pattern Prismatic No Background #384
 Noise  CC 0

Abstract Stars Geometric Pattern Prismatic No Background

Source GDJ

Carbon Fiber v2@2X #106
 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