MBossed@2X #194
 Grid  CC BY-SA 3.0

Embossed lines and squares with subtle highlights.

Source Alex Parker

 More Textures
Rough Cloth #312
 Fabric  CC BY-SA 3.0

More tactile goodness. This time in the form of some rough cloth.

Source Bartosz Kaszubowski

Fabric 1@2X #10
 Light  CC BY-SA 3.0

Semi-light fabric pattern made out of random pixels in shades of gray.

Source Atle Mo

Small Crackle Bright #352
 Light  CC BY-SA 3.0

Light gray pattern with an almost wall tile-like appearance.

Source Markus Tinner

Seamless tile 4 #1812
 Red  CC 0

Not strictly seamless in that opposite edges are not identical. But they do marry up to make an interesting pattern

Source Firkin

Vintage pattern 2 #2295
 Yellow  CC 0

Inspired by a pattern seen on a public domain image of a very old tile. To get the unit cell, select the rectangle in Inkscape and use shift+alt+i.

Source Firkin

Axiom Pattern@2X #331
 Grid  CC BY-SA 3.0

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

Source Struck Axiom

Prismatic Groovy Concentric Background 2 No Black@2X #456
 Noise  CC 0

Prismatic Groovy Concentric Background 2 No Black

Source GDJ

Background pattern 214 (colour 5) #2374
 Green  CC 0

A seamless chequerboard pattern formed from a tile that can be had in Inkscape by selecting the rectangle and using shift+alt+i. Alternative colour scheme.

Source Firkin

Starring@2X #586
 Dark  CC BY-SA 3.0

If you need stars, this is the one to get.

Source Agus Riyadi

Prismatic Geometric Pattern Background #407
 Noise  CC 0

Prismatic Geometric Pattern Background

Source GDJ

Prismatic Triangular Seamless Pattern III With Background #273
 Dark  CC 0

Prismatic Triangular Seamless Pattern III With Background

Source GDJ