A comeback for you: the popular Escheresque, now in black.
Source Patten
A seamless pattern the unit cell for which can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Sounds French. Some 3D square diagonals, that’s all you need to know.
Source Graphiste
Prismatic Isometric Cube Extra Pattern No Background
Source GDJ
A car pattern?! Can it be subtle? I say yes!
Source Radosław Rzepecki
Adapted heavily from a JPG that was uploaded to Pixabay by Viscious-Speed.
Source Firkin
A seamless texture of an abstract wall colored in shades of light orange brown.
Source V. Hartikainen
Prismatic Abstract Geometric Background 5 No Black
Source GDJ
Heavy depth and shadows here, but might work well on some mobile apps.
Source Damian Rivas
This is the remix of "plant pattern 02".I changed the object color to white and the BG to purple.The image a seamless pattern derived from a weed which I can't identify.The original weed image is from here:jp.pinterest.com/pin/500744052301423641/
Source Yamachem
The tile this is based on can be retrieved by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Simple wide squares with a small indent. Fits all.
Source Petr Šulc.
Everyone loves a diamond, right? Make your site sparkle.
Source AJ Troxell
Dark blue concrete wall with some small dust spots.
Source Atle Mo
Prismatic Groovy Concentric Background 4 No Black
Source GDJ
Seamless Light Background Texture.
Source V. Hartikainen
Design drawn in Paint.net, vectorised using Vector Magic and finished in Inkscape.
Source Firkin
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
Element of beach pattern with background.
Source Rones
A grid of squares with green colours. Since the colours are randomly distributed it is automatically seamless.
Source Firkin
Derived from an image that was uploaded to Pixabay by mdmelo.
Source Firkin
To get the tile this is based on select the rectangle in Inkscape and use shift+alt+i.
Source Firkin