Aside from Monero - Litecoin, Bitcoin Cash, Ethereum, and Nano are all interesting to me for different reasons, but they all have their own downsides of course.

Litecoin has MWEB (substantially better privacy than default Bitcoin - though not quite as good as Monero)

Bitcoin Cash has some new LargeInt operator thing that they're talking about building ZK privacy with

Eth has actual smart contracts and some privacy tech stuff though not as popular. Right now their L2s suck though all are centralized hopefully they fix that over time.

Nano is mostly interesting for it's DAG instant and feeless transactions, but it's DPoS so malicious actors can potentially censor the entire chain with only 34% stake, not as robust as PoW in that sense

Monero issuance is not predictable.

PoW can be changed to PoS or anything else if the validators want and it has already been changed in the past. It’s easier to change the consensus layer on these crypto because they can be “decentralized” but their consensus is not really distributed.