You have correctly listed, such as Litecoin, Dogecoin definitely faster than bitcoin, about Ethereum we can say that it is necessary, but it has decent competitors, which in their parameters are much better, but they have not yet caught up with Ethereum.
The coins I've mentioned previously, are among the fastest cryptocurrencies in existence. However, that could change, as the network load increases according to the number of users on the same. As far as I know, only 2 consensus algorithms seem to be the most scalable which are DPoS and DAG. Cryptocurrencies which make use of said algorithms can provide near-instant transactions and low costs. Some are even fee-less like EOS, NANO, and IOTA. This means that the future belongs to the next-generation of cryptocurrencies which are the fastest possible for worldwide transactions.
As such, the list of cryptocurrencies which are the fastest ones, is growing every day. Such list includes: EOS, IOTA, NANO, Constellation, IOST, Zilliqa, Ark, Bitshares, Lisk, Ripple, Stellar, DASH (Instant transactions), and even ByteBall. However, there could be more than that as new cryptocurrencies explore different technologies and features along the way. Therefore, I believe that those are the fastest cryptocurrencies in the meantime. Just my opinion
