The act or state of corrugating or of being corrugated, a wrinkle; fold; furrow; ridge.
Source Anna Litvinuk
To get the tile this is based on select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Not sure if this is related to the Nami you get in Google image search, but hey, it’s nice!
Source Dertig Media
The name alone is awesome, but so is this sweet dark pattern.
Source Federica Pelzel
This is the remix of "blue wave-seigaiha".The image depicts a seamless pattern of the front upper part of Japanese five yen coin which is used currently.This design represents a rice with ripe golden ears.
Source Yamachem
Could be paper, could be a Polaroid frame – up to you!
Source Chaos
From a drawing in 'In an Enchanted Island', William Mallock, 1892.
Source Firkin
Got some felt in my mailbox today, so I scanned it for you to use.
Source Atle Mo
This background pattern looks like bamboo to me. Feel free to download it for your website (for your blog perhaps?).
Source V. Hartikainen
The tile this fill pattern is based on can be had by using shift+alt+i on the rectangle.
Source Firkin
Derived from a drawing in 'The Murmur of the Shells', Samuel Cowen, 1879.
Source Firkin