More Textures
Background pattern 272 (colour 3) #2055
 Red  CC 0

A seamless pattern the unit cell for which can be had by selecting the rectangle in Inkscape and using shift+alt+i.

Source Firkin

Decorative divider 219 #2231
 Dark  CC 0

Remixed from a drawing in 'Maidenhood; or, the Verge of the Stream', Laura Jewry, 1876.

Source Firkin

Colorful Stripes Background #400
 Noise  CC 0

Colorful Stripes Background

Source GDJ

Carbon Fiber@2X #4
 Carbon  CC BY-SA 3.0

A dark pattern made out of 3×3 circles and a 1px shadow. This works well as a carbon texture or background.

Source Atle Mo

Prismatic Abstract Geometric Background 4 No Black@2X #442
 Dark  CC 0

Prismatic Abstract Geometric Background 4 No Black

Source GDJ

Soft Kill #318
 Dark  CC BY-SA 3.0

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

Source Factorio.us Collective

Retro Circles Background 5 No Black #426
 Noise  CC 0

Retro Circles Background 5 No Black

Source GDJ

Seamless Core Pattern 3 #167
 Dark  CC 0

Seamless Core Pattern 3

Source GDJ