SRV : Service locator (RFC 2782)
Generalized service location record, used for newer protocols instead of creating protocol-specific records such as MX.

MX : mail exchange record (RFC 1035)
Maps a domain name to a list of mail exchange servers for that domain

DNAME : delegation name (RFC 2672)
DNAME will delegate an entire portion of the DNS tree under a new name. In contrast, the CNAME record creates an alias of a single name. Like the CNAME record, the DNS lookup will continue by retrying the lookup with the new name.

DNSKEY : DNS Key record (RFC 4034)
The key record used in DNSSEC. Uses the same format as the KEY record.

NSEC3PARAM : NSEC3 parameters (RFC 5155)
Parameter record for use with NSEC3

AAAA : IPv6 address record (RFC 3596)
Returns a 128-bit IPv6 address, most commonly used to map hostnames to an IP address of the host.

TKEY : Transaction Key (RFC 2930)
One way of providing a key to be used with TSIG

LOC : Location record (RFC 1876)
Specifies a geographical location associated with a domain name

AFSDB : AFS database record (RFC 1183)
Location of database servers of an AFS cell. This record is commonly used by AFS clients to contact AFS cells outside their local domain. A subtype of this record is used by the obsolete DCE/DFS file system.

DS : Delegation signer (RFC 4034)
The record used to identify the DNSSEC signing key of a delegated zone

PTR : pointer record (RFC 1035)
Pointer to a canonical name. Unlike a CNAME, DNS processing does NOT proceed, just the name is returned. The most common use is for implementing reverse DNS lookups, but other uses include such things as DNS-SD.

NSEC : Next-Secure record (RFC 4034)
Part of DNSSEC—used to prove a name does not exist. Uses the same format as the (obsolete) NXT record.

HIP : Host Identity Protocol (RFC 5205)
Method of separating the end-point identifier and locator roles of IP addresses.

OPT : Option (RFC 2671)
This is a 'pseudo DNS record type' needed to support EDNS

NS : name server record (RFC 1035)
Delegates a DNS zone to use the given authoritative name servers

DLV : DNSSEC Lookaside Validation record (RFC 4431)
For publishing DNSSEC trust anchors outside of the DNS delegation chain. Uses the same format as the DS record. RFC 5074 describes a way of using these records.

TSIG : Transaction Signature (RFC 2845)
Record that supports one set of security mechanisms for DNS. Used to secure communication between DNS resolvers and Name servers, in contrast to DNSSEC, which secures the actual DNS records from the authoritative name server.

IXFR : Incremental Zone Transfer (RFC 1995)
Requests a zone transfer of the given zone but only differences from a previous serial number. This request may be ignored and a full (AXFR) sent in response if the authoritative server is unable to fulfill the request due to configuration or lack of required deltas.