This background pattern looks like bamboo to me. Feel free to download it for your website (for your blog perhaps?).
Source V. Hartikainen
Used in small doses, this could be a nice subtle pattern. Used on a large surface, it’s dirty!
Source Paul Reulat
Coming in at 666x666px, this is an evil big pattern, but nice and soft at the same time.
Source Atle Mo
Prismatic Rounded Squares Grid 4 No Background
Source GDJ
Could remind you a bit of those squares in Super Mario Bros, yeh?
Source Jeff Wall
Seamless pattern formed from a tile that can be extracted by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
Seamless Olive Green Web Background Image
Source V. Hartikainen
Prismatic Abstract Background Design
Source GDJ
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Everyone loves a diamond, right? Make your site sparkle.
Source AJ Troxell
Prismatic Floral Background No Black
Source GDJ
Simple gray checkered lines, in light tones.
Source Radosław Rzepecki
Bumps, highlight and shadows – all good things.
Source Badhon Ebrahim
A seamless pattern formed from miutopia's cakes on a tablecloth.
Source Firkin
Carbon fiber is never out of fashion, so here is one more style for you.
Source Alfred Lee
Luxurious looking pattern (for a T-shirt maybe?) with a hint of green.
Source Simon Meek
Prismatic Groovy Concentric Background No Black
Source GDJ
A new one called white wall, not by me this time.
Source Yuji Honzawa
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
Sweet and subtle white plaster with hints of noise and grunge.
Source Phil Maurer