See server.overview for articles concerning themselves with the opposite.

• usb.storage mount a local filesystem like ext3
• nfs.client mount a remote filesystem over NFS (contrary to nfs.server) recommended
• cifs.client mount a remote filesystem over CIFS (contrary to Samba)
• sshfs.client mount a remote filesystem over SSHFS (contrary to sshfs.server)

• snmp.client Act as an Simple Network Management Protocol client
• smtp.client Send mails over the SMTP
• smtps.client Send mails over Secure SMTP
• ntp.client get the time over Network Time Protocol
• DDNS receive a FQDN over Dynamic DNS from a DDNS-Service Provider