Sometimes simple really is what you need, and this could fit you well.
Source Factorio.us Collective
The tile this is formed from can be retrieved in Inkscape by selecting the rectangle and using shift+alt+i
Source Firkin
Prismatic Curved Diamond Pattern 3 No Background
Source GDJ
A nice looking light gray background pattern with diagonal stripes.
Source V. Hartikainen
Washi (和紙?) is a type of paper made in Japan. Here’s the pattern for you!
Source Carolynne
From a drawing in 'Friend or Fortune? The story of a strange year', Robert Overton, 1897.
Source Firkin
Honestly, who does not like a little pipe and mustache?
Source Luca Errico
Some more diagonal lines and noise, because you know you want it.
Source Atle Mo
A seamless pattern the starting point for which was a 'rainbow twist' texture in Paint.net.
Source Firkin
A seamless pattern from a tile made from a jpg on Pixabay. To get the tile select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
Remixed from a drawing in 'A Girl in Ten Thousand', Elizabeth Meade, 1896.
Source Firkin
The image depicts a seamless pattern of a Japanese family crest called "chidori" in Japanese .A chidori in Japanese means a plover in English.
Source Yamachem
Prismatic Abstract Background Design
Source GDJ
Prepared mostly as a raster in Paint.net and vectorised.
Source Firkin
Sort of like the back of a wooden board. Light, subtle, and stylish, just the way we like it!
Source Nikolalek
Formed by heavily distorting part of a an image of a fish uploaded to Pixabay by GLady
Source Firkin
Not so subtle. These tileable wood patterns are very useful.
Source Elemis
Fix and cc0 to get the tile this is based on.
Source SliverKnight
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
This one could be the shirt of a golf player. Angled lines in different thicknesses.
Source Olivier Pineda
It has waves, so make sure you don’t get sea sickness.
Source CoolPatterns
A topographic map like this has actually been requested a few times, so here you go!
Source Sam Feyaerts
A seamless web background with texture of aged grid paper.
Source V. Hartikainen
Abstract Geometric Monochrome Pattern Prismatic No Background
Source GDJ
To get the tile this is based on, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
A seamless web texture of "green stone".
Source V. Hartikainen
The image is a remix of "edo pattern-samekomon".I changed the color of dots from black to white and added BG in light-yellow.
Source Yamachem