IRC - IRC network on ports 6667 plaintext & 6697 TLS.
VPN - an invite only "non logging" wireguard VPN service.
Pubnix - another tilde service, accessed with SFTP on port 666.
syn.rip is a random server on the internet since 2021 running various daemons under OpenBSD. The services are available for public use. Some of which are invite only. You can usually recieve an invite to any of the various services by asking an admin or, depending on the service, another user.
These can also be used to connect to any of the services we run.