Basically all of them support some sort of lease mechanism to avoid one of the protocol phases in the common case. Virtually all of them provide snapshot reads

Basically all of them support some sort of lease mechanism to avoid one of the protocol phases in the common case. Virtually all of them provide snapshot reads as a performance / convenience thing. It's common for systems to use paxos as the configuration/topology layer while fine grained updates flow through something akin to viewstamped replication. Examples would be Kafka, Amazon Aurora.