Sometimes simple really is what you need, and this could fit you well.
Source Factorio.us Collective
A seamless pattern with green and yellow diagonal lines on top of a white dotted background.
Source V. Hartikainen
If you want png files of this u can download them here : viscious-speed.deviantart.com/gallery/27635117
Source Viscious-Speed
A seamless pattern formed from a sports car on clker.com. To get the tile, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
A green background pattern with warped vertical stripes and a grunge look.
Source V. Hartikainen
The tile for this is based on a repeating unit close to a design on Pixabay. It can be had by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
Derived from an image that was uploaded to Pixabay by darkmoon1968
Source Firkin
Here's a camo print with more tan and less green, such as might be used in a desert scenario. This is tileable, so it can be used as a wallpaper or background.
Source Eady
To get the tile this is based on select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Same as the black version, but now in shades of gray. Very subtle and fine grained.
Source Atle Mo
Original minus the background
Source Firkin
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
Bright Multicolored Floral Background by Karen Arnold from PDP.
Source GDJ
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
This is so subtle I hope you can see it! Tweak at will.
Source Alexandre Naud
A pattern derived from repeating unit cells each derived from part of a fractal rendering in paint.net.
Source Firkin
Pass parameters to the URL or edit the source code variables to configure the graph paper for the division desired.
Source JayNick
A background formed from an image of an old tile on the New York Metropolitan Museum of Art website. To get the base tile, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
It’s okay to be square! A nice light gray pattern with random squares.
Source Waseem Dahman
This is a seamless pattern which is derived from a flower petal image.
Source Yamachem