dig domain ANY
should give you all records. I write should because it depends on the DNS-Server used.
dig gmx.de ANY with my Telekom-DNS DNS-Servers 217.237.148.102 17.237.151.115 and only gives
;; ANSWER SECTION:
gmx.de. 65970 IN DS 26497 8 2 E7A00568AC320816600195F536B6BF2EEB06B0B2728146536FA53B22 45DDA66D
gmx.de. 65970 IN RRSIG DS 8 2 86400 20190812150105 20190805150105 47740 de. iKcp0dWmv1o/p4e31njqplr7noJE98ZEMfzjnSZ3XLqGvtSX8gVTBLVI yId8uMLvN/9NkRfzxELFiO9K3+x95lJnPrE0VpZoaGFpjYNIUOQhq7Xb tvWEXYH8y7XUw+VkSIJa3DQS7P/cNFGJ1/BinKIYtDn46PPNtdxFB+Tp Ee8=
Whereas dig gmx.de MX gives
;; ANSWER SECTION:
gmx.de. 474 IN MX 10 mx00.emig.gmx.net.
gmx.de. 474 IN MX 10 mx01.emig.gmx.net.
use dig gmx.de ANY @8.8.8.8 to query Google DNS and you get a long list.
;; ANSWER SECTION:
gmx.de. 23 IN A 82.165.229.87
gmx.de. 23 IN A 82.165.230.36
gmx.de. 23 IN RRSIG A 8 2 30 20190818065308 20190804065308 43065 gmx.de. Uh+KdZt/0mpk1JCjUmLFVHNaNnlv8zNRAc7ME0b9D/ULGHPmO6Ate9nG vFhcBC2c2ktJuqEw5pNieIVMLmkj9v7yzmccK0f1PwGgoW6IkuHxYVuN ExrWBpb0bHubF6xjMi8h3+JUd+kOEQdBX8XRAcVaxE9NTHkgqrFaZXjt NsICB0Hjq+LP7GfYTrRkaKsW9je5X6sfuBDDCtrc7MFJIm94Cm8mwD2d nVxD+1Bye+EXUbUjnaqjmJjXviK1GSaSRqiCcNd8TjBisBRQoKloxam9 NCikIMMEO5fAtAALtogxUtB3Znln0bKj7gTrOH21c5qC8LFyr7eVZoEN X9QXVQ==
gmx.de. 21593 IN NS ns-gmx.ui-dns.de.
gmx.de. 21593 IN NS ns-gmx.ui-dns.biz.
gmx.de. 21593 IN NS ns-gmx.ui-dns.com.
gmx.de. 21593 IN NS ns-gmx.ui-dns.org.
gmx.de. 21593 IN RRSIG NS 8 2 86400 20190818065308 20190804065308 43065 gmx.de. xY3gZxt47huiUseFZsbj4026RqGDZBuUCY9tv2CQmmpGUIH+YQLmQFKV xzZBS9MTnOIr2s4MMUbav7O/IaaCFlXb44gv4lCbjtSABQWF92rVZ1Js 89clPvLN5LUyzwBuEyx9Ew1dVvRGyJhG0icPPa6iFmpQvSLqwEEhck/H jOkFI99rWfM+gQRcYVvONlN5PP2idWOzeJpmg+BeSNDCTvtqFqMd+adS +uqooQarjcu6w3nGcOCnbdp//Ie2oXwXrVDDD3ntgJqktc4ggTaDoBnX Fbq2LXNejmHmM0VhmPRAAHGRyhjaaIVso8rqETz8fHTDNiS1k20mdF62 JyalPQ==
gmx.de. 21593 IN SOA ns-gmx.ui-dns.org. dnsadmin.1und1.de. 2013084217 28800 7200 604800 600
gmx.de. 21593 IN RRSIG SOA 8 2 86400 20190818065308 20190804065308 43065 gmx.de. C4Rhhfennofs0+Si8LyTs9FlMDXzaExKK60jFNvusx8ti06Vj7WPPXm8 +lc69v0AKGXzjnBqdR/Th8cTOC3eTwT/vJvV9k/UVJfN9/e8ASOjKY0P mHbBgH0VRqU1nHYOzVzuJkO2UIrZdMxIZYQ1gXmYK/4L2QL+iGUhTTJX /GKQKxRGi2YzgohpBx7Jtl3kYCcUudSq0zz3t2C7W6K6AKZC4B8cjOZU t+U678I1TRerLAzlaDmP2NbNrBhdG9CpUio4mW50X+59u2H4/NaGZ4Gm +LmeqLa6o88N6hutILfmyBLZGWD+j7mzDTjdXD2dvuIpjrQsHznvL7ZT ltQb4g==
gmx.de. 893 IN MX 10 mx00.emig.gmx.net.
gmx.de. 893 IN MX 10 mx01.emig.gmx.net.
gmx.de. 893 IN RRSIG MX 8 2 900 20190818065308 20190804065308 43065 gmx.de. g9qdLpwVTbLxaTa3CfSOTEZfUZWEf5RwCjaiquSpTQYgYEe+zDiGtd7I CnCQIgBVJIZUTBsXCbuPdd0qZzmGe8W2z9j/cz3WbQyf9ZIJrxZPDzV/ tnpB3j+GKmHkbuYg9CRw1ILpDBnvw6syV/z03nlH99eXWAee9b7S1Muk fIf6Xwt41hqyAof144jM/6GSaKfe4T1Rgc07i9LneHdt9n/C60Jo4aj9 bJ2Hdg9W1Fnd9aPg8xTt6Q+Ahz4kUR2hQSmwHLZnq36pIhkJkqxV+YPu etFtfERwyVW1eDPmG68tXqo4clBmtIzF0HqgxB0cdn8SgdlXs9lFqTgT 8RK+Rg==
gmx.de. 293 IN TXT "v=spf1 redirect=gmx.net"
gmx.de. 293 IN TXT "google-site-verification=8jV5RCya962H1ur14xR3xWCFUBsExt_YibC3HkuJ9X8"
gmx.de. 293 IN TXT "_telesec-domain-validation=D0B26BF4EFFDD17671E1967D1CC7F1DA06B99F496A3C52F2A7F81E7A70F463FD"
gmx.de. 293 IN RRSIG TXT 8 2 300 20190818065308 20190804065308 43065 gmx.de. tyRidjkmugwBfjjxcZgwXJk9ny/tEUD0unfvDUc0w8L7iG/QgXI5BnvO 0wU7EcwmJLkEyWUDu88KGiFK/HByW6oNpenz+1ZKD1uFKCOXccMClEHQ tbDDOkMmCCLzk17Jnz06oyhAVv50vNChtaCjKTz/+9IQi8LHyIi3KqNO C0doOvaaWjbF+C3Y7HZD7+PNjBXNmnvPjrTpxDsShcrVLYm6n38tNerk nZCD6gtFVnsSNy/zG2Ro+bma5oQMCkRPTUtWeVuIC/VitIYizVVqK3DO eDRyRpTe9HaFXXV0614GgxVjimbgsRXG2BcVz+M7410lIs4hjZkpE2+N YxAwsw==
gmx.de. 593 IN DNSKEY 256 3 8 AwEAAexRGtsaOHA3h7MCVG0AACIOr9DBpSNjh2N+kti0GYM448B6fyCS UGjA5VKzUq6szDQ4RDgJamDw/0pCWzFEjfKqD4glnyKzyALpkngznkDa 7I9kJo9gLt9BztCvthaMRHNfgDm2Rchfn8ahaPJXcHXMAPAuJmLYPdyd Pa21etNBCgEgmdLWNrY91FeSD40It1wqaw3i8O6yBgmRMz8JZV7kk3dH 2ocaS6WfgpAj+JzyG6CcPurv7zkq5/FQMOjF9vfNjtOhLAFDrm3fe4nW pcD9Gq864myFWDB1hcVjfRZ0370gjuZ5PxLyqlMVdpbKkkPX8L+p0iiM cHlGSKaoBJs=
gmx.de. 593 IN DNSKEY 257 3 8 AwEAAadAbK9K4yEQ6DC0jQMWYZH008gPUmBT7xIHPUIezY2/PGj5VTZy zNzpS+02jxaR86jmSo6d9zfpITwlLX730NwKP80D3Tpqu9W4h7x7/P+A ue8vjiqp148y2Ei/PG8/ePHs8C2QAUDMuKDGzffj/Rtji3rirT2p7/Vj vUByaT2+T9zzsenOyKJdULv6uZDUs5vkYBPRUWOXARKGII5sf2qrAo2P tr8bpynJE7CJHNg+UUGwb9ZpQ6lxBvKiFsPDB6kmYzUglfxpknyjs4bH vFsty1O7m6/cGRP+Vkz1vDhPBzENUvULegmMSQc/pzUNfI/LzzJiEu7R ZxP4Djcop/8=
gmx.de. 593 IN RRSIG DNSKEY 8 2 600 20190818065308 20190804065308 26497 gmx.de. H2/TQzTV+UEQbe9gqM5SIP/BtcoGrhNnkzwB3mVtFJwLfr2xMrv9HQT5 xKSVLLobjIUxoKq29qPKJ6OIzEMZY72Kcrd1xJ91U/e1aVLjxdUa67Wj ZCcsCxBx/xOWiFDmv6+8qxTmoFeHBg7BD92nRJLXqrzO7jHlIFstfvrJ U31YvlxY9e6o4WqSH3VoDHB8rmN52N6EMbGVwzhZRI2PGsaYv5eeibDp zbqAqJ//O+BIhS5jkdvXbV02erLApjzxe8sXTvAZpmgbH+DNmG8DTBZs 2oU3v+rsgFlwxp22d176mwQoVUWYof8xwEYGMgMuMM32nCu/iqsaW428 Fk5YiA==
gmx.de. 593 IN NSEC3PARAM 1 0 24 53DB50B23808A4C2
gmx.de. 593 IN RRSIG NSEC3PARAM 8 2 86400 20190818065308 20190804065308 43065 gmx.de. fnR7VcUl37Nw26t+ZmbwHmjLm/znrBjZkPCVRW6ca25FtAUeOAJ3tdVy faPy0KHf87sfD8NVu134tLC4pd2NP5ELkQZM5jEhpVJF55Og6y1pFSFK +6TFPvXbw93SW3ZhTJOHhU9D/suPvvAfyYtQDvzE7WtHN/u/XfGK9F8/ BJzTUACwer+y7fk8xuUjmOa29Y4oH6/g/AZNkOuvsWZ1npH/StHxOAtM EI0g/XTDJ4w5rji8cdGVcBzhNOfUFhaInVLgeFm6PXd9gXtnzbrkC2ha 3vBT3S4wYEM8YEW6H1A8zHcNS6eA1cuCTHfGPaU1dqoZ4ujOIE05C/YQ YgWOfg==
gmx.de. 21593 IN CAA 0 issue "Digicert.com"
gmx.de. 21593 IN CAA 0 issue "telesec.de"
gmx.de. 21593 IN RRSIG CAA 8 2 86400 20190818065308 20190804065308 43065 gmx.de. TG3BUmiwib0qvBQ127aIAG89SwdD46UuBy0wK1ohOc0xoP36fSh3g30G PUU7OGBCgaCapwzxCON+gGY7xCkD37cZt8ydzBCxFGvWyf0PvObicgrY /DjLuWOOJLJjNv8Ab3mg+vVD0Dki4ZEodrKU9pv8B204afee2OQFFXs7 bfDJrllvqQ8mX8nd6ou5+21+cwldF/uRP/t4GM0qIf1fajZsgmqoHQ8t ARzBWlZix4SlpKoOyvGjjHGnpCTsOWHlWB1UU/SUnmPIGh1dDq/Go+PN z7zT2khWQy2xYJPd4Cg/HHzfBT1CvTg3C25ncj/BEHCcbHnjMNx2vtms OCwyog==
However using QuadNine dig gmx.de ANY @9.9.9.9 we only get
;; ANSWER SECTION:
gmx.de. 22680 IN DS 26497 8 2 E7A00568AC320816600195F536B6BF2EEB06B0B2728146536FA53B22 45DDA66D
gmx.de. 22680 IN RRSIG DS 8 2 86400 20190812150105 20190805150105 47740 de. iKcp0dWmv1o/p4e31njqplr7noJE98ZEMfzjnSZ3XLqGvtSX8gVTBLVI yId8uMLvN/9NkRfzxELFiO9K3+x95lJnPrE0VpZoaGFpjYNIUOQhq7Xb tvWEXYH8y7XUw+VkSIJa3DQS7P/cNFGJ1/BinKIYtDn46PPNtdxFB+Tp Ee8=
So try different DNS-Servers to really get all DNS-Records or query for specific records directly.