I’ve used herbstluftwm on my main desktop for years. Love it. Manual tiling works well for me. Totally flexible and customizable. Switch between floating and tiling with a keypress, etc.
And then on various other machines.
Xfce on my desktop at work that I don’t use that much (work mainly from home) and just needed to set up quick. It’s totally fine, like xfce always is.
Gnome on my tablet (basically a Surface knock-off). I don’t really like gnome, but it’s the only thing I’ve tried that works well OOTB for a touchscreen.
PekWM on an old macbook running debian. Great stacking WM. Super flexible, and the tabbed windows for any app are cool.
LXQT on an ancient (2009?) dual-core laptop that I mainly just use for writing in nvim. Works well for a simple setup.
Linux Mint Debian Edition. Very windows-like + automatic updates = ideal for people who don’t really want to have to learn anything new (assuming your parents are like mine in that respect).