One subject I've been really interested in lately are mechanics where players are eliminated just before determining the winner as in High Society, Lords of Xidit and Gùgōng.
I spent the last few months collecting all the various examples I could find into a few categories of "qualifiers".
Part I covers Comparative Qualifiers where players are evaluated and the weakest performer in a specific criterion is eliminated.
Part II covers Absolute Qualifiers where players must complete a specific task or avoid a specific outcome in order to remain eligible to win.
I always enjoy hearing commentary and criticism from other designers.