Are there any applications of NFT collections as leaderboards? 

The same NFT switches hands based on who has the verifiably highest score in a game or anything else

New Yoink works this way. The flag changes hands and a trophy token is transferred to the Top Yoinker.

yoink.party/frames

I'm eth newbie..just learning
(working on @farcaster)

terminally.online

Interesting. For whatever reason I was thinking about educational game leaderboards for kids. Anything from in class games as formative assessments where it changes hands to something like College Board doing it for highest SAT and every AP test. But the decentralized aspect doesn’t really gel with that super well