Sometimes simple really is what you need, and this could fit you well.
Source Factorio.us Collective
A mid-tone gray pattern with some cement looking texture.
Source Hendrik Lammers
To get the tile this is based on, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
Actually, there's no clouds in it, but I think it looks quite nice.
Source V. Hartikainen
Light and tiny, just the way you like it.
Source Rohit Arun Rao
From a drawing in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892.
Source Firkin
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
I asked Gjermund if he could make a pattern for us – result!
Source Gjermund Gustavsen
Seamless Background For Websites. It has a texture similar to cork-board.
Source V. Hartikainen
Derived from an image that was uploaded to Pixabay by TheDigitalArtist
Source Firkin
From a design found in 'History of the Virginia Company of London; with letters to and from the first Colony, never before printed', Edward Neill, 1869.
Source Firkin
A bit like smudged paint or some sort of steel, here is scribble light.
Source Tegan Male
A seamless chequerboard pattern formed from a tile that can be had in Inkscape by selecting the rectangle and using shift+alt+i. Alternative colour scheme.
Source Firkin
Sort of reminds me of those old house wallpapers.
Source Tish
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
All good things come in threes, so I give you the third in my little concrete wall series.
Source Atle Mo
A background tile of dark textile. Made this a long time ago and just now decided to publish it.
Source V. Hartikainen
A free background tile with a pattern of pink bump dots. This background tile is sweet! Moreover, it's designed for use as website backgrounds.
Source V. Hartikainen
From a drawing in 'Artists and Arabs', Henry Blackburn, 1868
Source Firkin
This is the remix of "Tileable Wave Pattern 2" uploaded by "Arvin61r58".Thanks.I added a wire-mesh fence seamless pattern as a lower layer.
Source Yamachem
Seamless pattern the tile for which can be had by using shift-alt-I on the selected rectangle in Inkscape.
Source Firkin