So your environment got bigger fast and you have a TON of forward and reverse lookup zones and something is out of whack. Well, I have a tool I've made in PowerShell and used successfully to 1) Find DNS A and PTR records related to specific hostnames or IPs and 2) Update their records like adjusting TTL and bulk renaming to point to a new host and 3) Make a backup of the existing records just in case as a CSV file ^_^).
This is probably one of the scariest tools I've had to build and comes with ZERO warranty - because, seriously, this is manipulating DNS records in bulk - but if you want to even just check to see what A or PTR records exist for a single IP then this might help you. You just run the tool as an admin on a Domain Controller, it IS interactive, and it will tell you that it may take several minutes to retrieve all A and PTR records and mesh them together. After that, it presents a menu to work with. I'm always open to tweaking ideas like I want to, at some point, have an option to just delete all orphaned objects or force re-create PTR records for all A records that are missing them...but that gets weird when you have load balancers and web apps where a ton of stuff should or should not point to one IP. Have fun!
Requires the DNSServer module from RSAT and to be run locally as an admin on the DC. Here's the link to the script: