Compare answers from two resolvers

Spot split-horizon or stale cache differences between resolvers

diff <(dig +short @1.1.1.1 example.com) <(dig +short @8.8.8.8 example.com)

More dig commands

Reverse PTR lookup for IPv6

dig -x 2606:4700:4700::1111 +short

PTR for an IPv6 address; -x expands nibble format automatically
Query TXT/SPF, DKIM and DMARC at once

for r in example.com _dmarc.example.com sel._domainkey.example.com; do dig +short TXT $r; done

Pull SPF, DMARC and DKIM TXT records in one loop for mail audits
Check CAA records before issuing certs

dig +short CAA example.com

Show which CAs may issue certs; missing CAA lets any CA issue
Resolve SRV records for service discovery

dig +short SRV _sip._tcp.example.com

Get priority/weight/port/target for a service; used by AD, SIP, XMPP
Force TCP and show remaining TTL

dig +tcp +ttlunits +noall +answer example.com @8.8.8.8

Test TCP/53 reachability; +ttlunits prints TTL as 1h/30m not raw seconds