Sometimes simple really is what you need, and this could fit you well.
Source Factorio.us Collective
A seamless pattern created from a square tile. To get the tile, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
A seamless texture of an abstract wall colored in shades of light orange brown.
Source V. Hartikainen
Inspired by this, I came up with this pattern. Madness!
Source Atle Mo
A seamless pale yellow paper background with a pattern of animal tracks.
Source V. Hartikainen
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
A seamless pattern the starting point for which was a 'rainbow twist' texture in Paint.net.
Source Firkin
Derived from a corner decoration itself found as a jpg on Pixabay.
Source Firkin
Seamless Olive Green Web Background Image
Source V. Hartikainen
This is the remix of "polka dot seamless pattern".The image depicts polka dot seamless pattern.
Source Yamachem
From a drawing in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892.
Source Firkin
An interesting dark spotted pattern at an angle.
Source Hendrik Lammers
Could be paper, could be a Polaroid frame – up to you!
Source Chaos
Background pattern made in "Grunge-Like" style. Available in both SVG and JPG formats. Edit to your needs then click the download button.
Source V. Hartikainen
Zero CC Mossy stone tileable texture, photographed and made by me. CC0
Source Sojan Janso
A seamless pattern based on a tile that can be achieved by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Nice little grid. Would work great as a base on top of some other patterns.
Source Arno Gregorian
Alternative colour scheme. Not a pattern for fabrics, but one produced from a jpg of a stack of fabric items that was posted on Pixabay. The tile that this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
No relation to the band, but damn it’s subtle!
Source Thomas Myrman
Don’t look at this one too long if you’re high on something.
Source Luuk van Baars
From a drawing in 'Chambéry à la fin du XIVe siècle', Timoleon Chapperon, 1863.
Source Firkin
Run a restaurant blog? Here you go. Done.
Source Andrijana Jarnjak