`etcd` is probably the canonical off-the-shelf solution. Other implementations are listed here https://raft.github.io/#implementations

Consul[0] and Nomad [1] by HashiCorp both use raft.

[0] https://consul.io

[1] https://nomadproject.io

As does RabbitMQ, Docker Swarm, AlertManager (prometheus addon).

If you run any of these systems in production, it is good to have a cursory understanding.

Zookeeper is the standard one which has been around the oldest. Zookeeper is not based on raft, but it has similar semantics as etcd. So if you don't care about the impl, ZK may be good as well.

The Zookeeper consensus algorithm is called Zookeeper Atomic Broadcast (ZAB).

YugabyteDB https://blog.yugabyte.com/how-does-the-raft-consensus-based-...

And CockroachDB both use raft consensus https://www.cockroachlabs.com/docs/stable/architecture/repli...

If you want a library and not a fully-fledged raft-backed KV daemon/service, there's also dragonboat [1].

[1] - https://github.com/lni/dragonboat