More Textures
Ribbon pattern 2 (version 2, colour 6) #2034
 Pink  CC 0

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

Source Firkin

Axiom Pattern #330
 Grid  CC BY-SA 3.0

Not even 1kb, but very stylish. Gray thin lines.

Source Struck Axiom

Background pattern 269 #2062
 Dark  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

Old Mathematics #43
 Stripes  CC BY-SA 3.0

This one takes you back to math class. Classic mathematic board underlay.

Source Josh Green

Transparent Square Tiles@2X #299
 Grid  CC BY-SA 3.0

The first pattern on here using opacity. Try it on a site with a colored background, or even using mixed colors.

Source Nathan Spady

Prismatic Groovy Concentric Background No Black@2X #452
 Noise  CC 0

Prismatic Groovy Concentric Background No Black

Source GDJ

Prismatic Basic Pattern 2 No Background@2X #448
 Noise  CC 0

Prismatic Basic Pattern 2 No Background

Source GDJ