Bitcoin Q&A: Altcoins and Specialisation

What other crypto-assets and technologies interest you besides Bitcoin and Ethereum? I'm interested in the cryptocurrencies that are pioneering privacy and anonymity, such as Monero and Zcash. I'm interested in resource-sharing ones as well. It is less likely that they will be eclipsed by Bitcoin and its second layers as long as they maintain that privacy-conscious differentiation.
Is Litecoin still "the silver to bitcon's [digital] gold"? Litecoin often follows the core roadmap, but it has filled a niche of rapid development that acts as a testing ground for innovations that may end up in Bitcoin. I think there is room for multiple cryptocurrencies that have less adoption overall but are "apex" in certain categories.