Interesting. All enticing choices. I will them all, one by one. Yep, I remember twm. I thought it was an interesting upgrade from mwm.
I used fwvm for a long time. I had it mostly keyboard-driven.
I personally don't get the improvements in the newer or latest-greatest WM, they seem like a step back, too complicated with too many options and lacking features I found critical. Say gnome for example, I have to make too many changes to it to make look palatable to me.
It's helpful to differentiate between a window manager, and a Desktop Environment.
A window manager, such as most of those on the wikipedia page linked in post #5 is basically a small executable that manages the windows by positioning them, enabling them to move about, resizing them, maybe providing icons and menus, and not much else if anything, (but note the caveat at the end).
A Desktop Environment like gnome or KDE includes a window manager, but beyond that includes numerous programs which are over and above the relatively simple function of a window manager in order to enable an enhanced fully-featured experience for the user.
Here is a brief comparison between what the window managers twm and icewm supply, compared to what gnome supplies for its Desktop Environment (DE):
The output from the tab completion shows the executable window manager twm as a single executable.
Code:
apt show icewm <TAB>
icewm icewm-common icewm-experimental icewm-lite
The output shows the few icewm programs for the window manager, only two of which are needed to run icewm, the first and second.
Code:
apt show gnome <TAB>
Display all 182 possibilities? (y or n)
gnome gnome-dust-icon-theme gnome-paint gnome-shell-extension-runcat
<snip>
For the gnome Desktop Environment there are on this system 182 programs with the gnome name in them. I've spared the reader the large output they can investigate for themselves.
About 30 gnome packages/applications, form the core of gnome and are needed to get a basic gnome DE. However the fully featured DE includes more.
The gnome DE, in addition to the window manager, (the default one being mutter), includes a file manager, numerous GUI front-ends for services including for network managing, for a sound server, for system daemons like journald and packagekit, for video viewing. There's a GUI text editor, a web browser, document viewer, image viewer, GUIs for system analysis tools, image manipulation programs, games, and heaps more that can be seen from the apt command above. There are numerous other programs that don't have "gnome" in their name which also form part of gnome's DE which can be found here:
https://apps.gnome.org/
The caveat in relation to window managers, is that some which began as primarily programs for window management, did accumulate functions which started to make them look like they were on the way to becoming DEs themselves. The main one in that respect in my experience was Enlightenment.