A monochrome pattern from a tile that can be had by selecting the rectangle in Inkscaope and using shift+alt+i
Source Firkin
Heavy depth and shadows here, but might work well on some mobile apps.
Source Damian Rivas
Continuing the geometric trend, here is one more.
Source Mike Warner
Remixed from a raster on Pixabay, that was uploaded by ArtsyBee.
Source Firkin
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
Zero CC tileable Crackled Cement (streaks) texture, photographed and made by me. CC0
Source Sojan Janso
Redrawn based on a drawing in 'По Сѣверо-Западу Россіи' Konstantin Sluchevsky, 1897.
Source Firkin
8 by 8 pixels, and just what the title says.
Source pixilated
This reminds me of Game Cube. A nice light 3D cube pattern.
Source Sander Ottens
A seamless pattern formed from a tile made from page ornament 22. To get the tile, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
And some more testing, this time with Seamless Studio. It’s Robots FFS!
Source Seamless Studio
Formed from a tile based on a drawing from 'Viaggi d'un artista nell'America Meridionale', Guido Boggiani, 1895.
Source Firkin
Actually, there's no clouds in it, but I think it looks quite nice.
Source V. Hartikainen
ZeroCC tileabel stone granite texture, edited from pixabay. CC0
Source Sojan Janso
To get the tile this is based on, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
Subtle scratches on a light gray background.
Source Andrey Ovcharov
Remixed from a design seen in 'Burghley. The Life of William Cecil', William Charlton, 1857. The tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Prismatic Hypnotic Pattern No Background
Source GDJ
Remixed from a drawing in 'Prehistoric Man: researches into the origin of civilisation in the old and the new world', Daniel Wilson, 1876.
Source Firkin
This is a remix of "blue wave-seigaiha".I hope this subtle color version of Seigaiha would be suitable for background .
Source Yamachem
Original minus the background
Source Firkin
One more sharp little tile for you. Subtle circles this time.
Source Blunia
Derived from elements found in a floral ornament drawing on Pixabay.
Source Firkin