Sometimes simple really is what you need, and this could fit you well.
Source Factorio.us Collective
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
Same as the black version, but now in shades of gray. Very subtle and fine grained.
Source Atle Mo
Simple gray checkered lines, in light tones.
Source Radosław Rzepecki
From a drawing in 'Studies for Stories', Jean Ingelow, 1864.
Source Firkin
A seamless pattern created from a square tile. To get the tile, select the pattern in Inkscape and use shift+alt+i.
Source Firkin
Seamless pattern formed from a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
A seamless pattern of dark bricks. Maybe it's not very realistic, but it looks good in my opinion.
Source V. Hartikainen
This one takes you back to math class. Classic mathematic board underlay.
Source Josh Green
From a drawing in 'Storia del Palazzo Vecchio in Firenze', Aurelio Gotti, 1889.
Source Firkin
Prismatic Geometric Tessellation Pattern 3 No Background
Source GDJ
Heavy depth and shadows here, but might work well on some mobile apps.
Source Damian Rivas
Seamless Green Tile Background
Source V. Hartikainen
Remixed from a drawing in 'Chambéry à la fin du XIVe siècle', Timoleon Chapperon, 1863.
Source Firkin
The name is totally random, but hey, it sounds good.
Source Atle Mo
Can’t believe we don’t have this in the collection already! Slick woven pattern with crisp details.
Source Max Rudberg
Inspired by a JPG that was uploaded to Pixabay by kokon_art
Source Firkin
Design drawn in Paint.net, vectorised using Vector Magic and finished in Inkscape.
Source Firkin
Looks like a technical drawing board: small squares forming a nice grid.
Source We Are Pixel8
This is the remix of "blue wave-seigaiha".This is the flowers of pink silk tree which is called "nemuno-ki".About pink silk tree ,refer to here:https://jp.pinterest.com/pin/500744052301210439/
Source Yamachem
Seamless pattern formed from a tile that can be had by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
Colored maple leaves scattered on a surface. This is tileable, so it can be used as a background or wallpaper.
Source Eady