Sometimes simple really is what you need, and this could fit you well.
Source Factorio.us Collective
Never out of fashion and so much hotter than the 45º everyone knows, here is a sweet 60º line pattern.
Source Atle Mo
A lovely light gray pattern with stripes and a dash of noise.
Source V. Hartikainen
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
A seamless web background with texture of aged grid paper.
Source V. Hartikainen
Same as gray sand but lighter. A sandy pattern with small light dots, and some angled strokes.
Source Atle Mo
Prismatic 3D Isometric Tessellation Pattern 6
Source GDJ
Neat little photography icon pattern.
Source Hossam Elbialy
From a drawing in 'Line and form', Walter Crane, 1914.
Source Firkin
This is so subtle: We’re talking 1% opacity. Get your squint on!
Source Atle Mo
An abstract Background pattern of purple twisty patterns.
Source TikiGiki
Embossed lines and squares with subtle highlights.
Source Alex Parker
A bit strange this one, but nice at the same time.
Source Diogo Silva
I’m starting to think I have a concrete wall fetish.
Source Atle Mo
From a drawing of the coat of arms of the Ottoman Empire on Wikimedia.
Source Firkin
Could be paper, could be a Polaroid frame – up to you!
Source Chaos
Seamless Olive Green Web Background Image
Source V. Hartikainen
A background pattern with wavy green vertical stripes. This one has green stripes on a white background. Download if you like it.
Source V. Hartikainen
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
To get the tile this is formed from select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
The image depicts a seamless pattern of the design which includes a stylized lotus and a stylized crane.I referred to the original image in a book which is into public domain.
Source Yamachem