An important difference between Wayland and X11 is that Wayland by concept combines window manager and compositor. That made it harder to write simple or experimental window managers for Wayland, such as StumpWM or i3.

River is a compositor for Wayland that supports implementing a window manager separately, with an independent window placement paradigm, in an arbitrary language, for example Python, Lisp, Rust, zig, C, Janet - you get it.

Here is the wiki page listing 26 different window managers for river:

https://codeberg.org/river/wiki/src/branch/main/pages/wm-list.md

Some of these are only 600 lines of code in a Lisp-like language (Janet).

The ones I find most interesting are mousetrap and mopotamo - I am a big fan of StumpWMs manual tiling and configurability.