None for email, unless you roll your own[0][1][2][3][4].

[0] https://github.com/foxcpp/maddy

[1] https://github.com/LukeSmithxyz/emailwiz

[2] https://github.com/iredmail/iRedMail

[3] https://github.com/Mailu/Mailu

[4] https://github.com/docker-mailserver/docker-mailserver