Monero's RandomX is an interesting PoW scheme one designed to be optimized for CPUs. Here is an interesting read about its design https://github.com/tevador/RandomX/blob/master/doc/design.md

Chia uses a very memory-hard PoW system and is usually mined on SSDs.

I've seen a lot of "useful PoW" cryptocurrencies, but they tend to not pan out. For example Gridcoin is just a Proof-of-Stake cryptocurrency with a program that hands out GRC to BOINC contributors.