All queries can be appended with @NAMESERVER where NAMESERVER is the DNS server you wish to interrogate.

DNS Forward Lookup

dig example.com

DNS Reverse Lookup

dig -x 1.2.3.4

DNS Specific Record Lookup

dig TYPE example.com

Replace TYPE with the type of record you want, for example a, mx or txt.

DNS Zone Transfer

Very useful when trying to enumerate hosts on a domain. Usually disabled but very handy if enabled when pentesting.

dig axfr example.com