Repmgr is handy, but it is not a replication system per se, but rather makes managing a bunch of moving other parts easier.

Personally I'd like BDR to be in the main tree, or something else, equivalent to Galera:

* https://galeracluster.com

It's not perfect [1], but it'll get you a good way for many use cases.

[1] https://aphyr.com/posts/327-jepsen-mariadb-galera-cluster