Sometimes simple really is what you need, and this could fit you well.
Source Factorio.us Collective
Remixed from a drawing in 'Hungary. A guide book. By several authors', 1890.
Source Firkin
Seamless pattern formed from a tile that can be extracted by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
A blue background wallpaper for websites. It has a seamless texture with vertical stripes. It looks quite nice not only when using as a tiled background on websites, but also on computer desktops.
Source V. Hartikainen
Not the Rebel alliance, but a dark textured pattern.
Source Hendrik Lammers
Adapted heavily from a JPG that was uploaded to Pixabay by Viscious-Speed.
Source Firkin
Remixed from a drawing in 'A Child of the Age', Francis Adams, 1894.
Source Firkin
A seamless pattern formed from a tile that can be had in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin
Here's a seamless brown cork board background texture. Feel free to download or reshare if you like.
Source V. Hartikainen
A seamless pattern the starting point for which was a 'rainbow twist' texture in Paint.net.
Source Firkin
Sort of like the Photoshop transparent background, but better!
Source Alex Parker
Greyscale version of a pattern that came out of playing with the 'slinky' plug-in for Paint.net
Source Firkin
Prismatic Geometric Tessellation Pattern 3 No Background
Source GDJ
To get the tile this is formed from select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Have you wondered about how it feels to be buried alive? Here is the pattern for it.
Source Hendrik Lammers
This is the remix of "Colorful Floral Pattern Background 3" uploaded by "GDJ". Thanks.
Source Yamachem
A seamless design of flowers remixed from a jpg on Pixabay by Prawny.
Source Firkin
Seamless Prismatic Pythagorean Line Art Pattern No Background. A seamless pattern that includes the original tile (go to Objects / Pattern / Pattern To Objects in Inkscape's menu to extract it).
Source GDJ
Zero CC tileable seed texture, edited by me to be seamless from a Pixabay image. CC0
Source Sojan Janso
Remixed from a drawing in 'The March of Loyalty', Letitia MacClintock, 1884.
Source Firkin
A chequerboard pattern with a fruit theme. The fruits are from a posting by inkscapeforum.it.
Source Firkin
Stefan is hard at work, this time with a funky pattern of squares.
Source Stefan Aleksić