A comeback for you: the popular Escheresque, now in black.
Source Patten
Zero CC tileable hard cover green book, scanned and made by me. CC0
Source Sojan Janso
This one could be the shirt of a golf player. Angled lines in different thicknesses.
Source Olivier Pineda
Nice little grid. Would work great as a base on top of some other patterns.
Source Arno Gregorian
This was formed by distorting an image of a background on Pixabay.
Source Firkin
Remixed from a drawing in 'Analecta Eboracensia', Thomas Widdrington, 1897.
Source Firkin
Colorful Floral Background 3 No Black
Source GDJ
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
It almost looks a bit blurry, but then again, so are fishes.
Source Petr Šulc
A seamless pattern that includes the original tile (go to Objects / Pattern / Pattern To Objects in Inkscape's menu to extract it).
Source GDJ
A light background pattern with diagonal stripes. Here's a simple light striped background for you.
Source V. Hartikainen
Utilising some flowers from Almeidah. To get the unit tile, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin