out of curiosity, what do you have so far from the usual topics?

> > Are there good motivational examples that fit in a couple of pages? And/or are there good free software or source-available programs and libraries that are worth citing and sending my readers to, to illustrate the power and interest of those techniques?

I've made a few examples on my blog:
https://turtleware.eu/posts/Method-Combinations.html    -- couple of method combinations
https://turtleware.eu/posts/Proxy-Generic-Function.html -- proxying function methods to another generic function
https://turtleware.eu/posts/Dynamic-Vars---Return-of-the-Jedi.html -- thread-local variables ala ContextL

Timothy Moore came up with a clever way to parametrize standard classes in McCLIM:
https://www.jucs.org/jucs_14_20/an_implementation_of_clim/jucs_14_20_3358_3369_moore.pdf