More Textures
Colorful Floral Background 3 No Black@2X #486
 Light  CC 0

Colorful Floral Background 3 No Black

Source GDJ

Tessellation 15 #2223
 Dark  CC 0

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

Source Firkin

Retro Squares Background 9 #399
 Dark  CC 0

Retro Squares Background 9

Source GDJ

White carbon #11
 Carbon  CC BY-SA 3.0

Same as the black version, but now in shades of gray. Very subtle and fine grained.

Source Atle Mo

Seamless Core Pattern 5 #169
 Dark  CC 0

Seamless Core Pattern 5

Source GDJ