Also try LXDE and LXQT if you would like a 'lighter KDE' vibe instead of the 'lighter gnome 2' vibe of XFCE.
LXQt is great, except for the fact it can only do 'regular, italic, bold, bold italic' for font weights even when a font supports medium (my preferred font weight, regular just seems so dainty now I've gotten used to medium).
I also like the fact that it allows use of any window manager and even supports Wayland now (so Wayfire is an option).
Yep LXQt is a beast, super snappy and complete. I use it on an old laptop (2012) and it still works great with a very low memory footprint (much lower than XFCE when I tested a bunch of them).