This beige background pattern resembles a concrete wall with engravings or something similar to it.
Source V. Hartikainen
From a tile that 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 Kaz
Source Firkin
A subtle shadowed checkered pattern. Increase the lightness for even more subtle sexiness.
Source Josh Green
Drawn in Paint.net and vectorised in Vector Magic.
Source Firkin
Small dots with minor circles spread across to form a nice mosaic.
Source John Burks
Utilising some flowers from Almeidah. To get the unit tile, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
A dark one with geometric shapes and dotted lines.
Source Mohawk Studios
Remixed from a drawing in 'Some account of the Worshipful Company of Ironmongers', John Nicholl, 1866.
Source Firkin
Super detailed 16×16 tile that forms a beautiful pattern of straws.
Source Pavel
White fabric looking texture with some nice random wave features.
Source Hendrik Lammers
Super subtle indeed, a medium gray pattern with tiny dots in a grid.
Source Designova
A light gray fabric pattern with faded vertical stripes.
Source V. Hartikainen
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Bright Multicolored Floral Background by Karen Arnold from PDP.
Source GDJ
And some more testing, this time with Seamless Studio. It’s Robots FFS!
Source Seamless Studio
Abstract Tiled Background Extended 8
Source GDJ
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Non-seamless pattern drawn in Paint.net and vectorised in Vector Magic.
Source Firkin
Seamless pattern formed from a tile that can be extracted by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin