More Textures
Soft Kill #318
 Dark  CC BY-SA 3.0

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

Source Factorio.us Collective

Graphy #350
 Grid  CC BY-SA 3.0

Looks like a technical drawing board: small squares forming a nice grid.

Source We Are Pixel8

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

High detail stone wall with minor cracks and specks.

Source Projecteightyfive

Brushed Alum #67
 Light  CC BY-SA 3.0

A light brushed aluminum pattern for your pleasure.

Source Tim Ward

Background pattern 339 (colour 2) #1707
 Green  CC 0

The tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i

Source Firkin

Little Pluses #73
 Light  CC BY-SA 3.0

Subtle grunge and many little pluses on top.

Source Atle Mo

Retro Circles Background 4 No Black@2X #423
 Dark  CC 0

Retro Circles Background 4 No Black

Source GDJ

Abstract Ellipses Background Grayscale #378
 Dark  CC 0

Abstract Ellipses Background Grayscale

Source GDJ

Abstract Tiled Background Extended 7 #518
 Dark  CC 0

Abstract Tiled Background Extended 7

Source GDJ

Seamless Prismatic Pythagorean Line Art Pattern No Background@2X #570
 Light  CC 0

Seamless Prismatic Pythagorean Line Art Pattern No Background. A seamless pattern that includes the original tile (go to Objects / Pattern / Pattern To Objects in Inkscape's menu to extract it).

Source GDJ