This light blue background pattern is quite pleasing to the eye, it consists of a tiny rough grid pattern, which is seamless by design. That's it, if you like the color, you can use this seamless pattern in a web design without making any further modifications to it.
Source V. Hartikainen
A seamless green background texture. The image is distributed under a Creative Commons License (like all of the images here).
Source V. Hartikainen
Formed by distorting the inside front cover of 'Diversæ insectarum volatilium : icones ad vivum accuratissmè depictæ per celeberrimum pictorem', Jacob Hoefnagel, 1630.
Source Firkin
Used a cherry by doctormo to make this seamless pattern
Source Firkin
From a drawing in 'Resa i Afrika, genom Angola, Ovampo och Damaraland', P. Moller, 1899.
Source Firkin
A seamless background pattern with a texture of wood planks. This wood background pattern has vertically arranged planks. You may try to rotate it 90°, to see how it will look like when the wood planks are arranged horizontally.
Source V. Hartikainen
Remixed from a drawing in 'The March of Loyalty', Letitia MacClintock, 1884.
Source Firkin
You can never get enough of these tiny pixel patterns with sharp lines.
Source Designova
Not sure if this is related to the Nami you get in Google image search, but hey, it’s nice!
Source Dertig Media
The first pattern on here using opacity. Try it on a site with a colored background, or even using mixed colors.
Source Nathan Spady
Neat little photography icon pattern.
Source Hossam Elbialy
From a drawing in 'At home', J. Sowerby, J. Crane and T. Frederick, 1881.
Source Firkin
Colour version of the original pattern.
Source Firkin
An abstract web texture of a polished blue stone (or does it look more like ice).
Source V. Hartikainen
This is the remix of "plant pattern 02".I changed the object color to white and the BG to purple.The image a seamless pattern derived from a weed which I can't identify.The original weed image is from here:jp.pinterest.com/pin/500744052301423641/
Source Yamachem
From a drawing in 'An Old Maid's Love. A Dutch tale told in English', Maarten Maartens, 1891.
Source Firkin
Can never have too many knitting patterns, especially as nice as this.
Source Victoria Spahn
Same as gray sand but lighter. A sandy pattern with small light dots, and some angled strokes.
Source Atle Mo
I know there is one here already, but this is sexy!
Source Gjermund Gustavsen
Feel free to use this seamless background texture as a background on a web site. It's colored in a light pink color and is seamlessly tile-able.
Source V. Hartikainen