Since I am now running my own smtp-server, I have to deal with different black list servers myself and check my IP from time to time if it’s there or not.To cover pretty much everything valuable:
My IP was in 2 lists, DAN ME, APEWS and Barracuda.
DAN ME is a list maintained by some loser, who lists there all TOR-related IP addresses he can find. Unfortunately he lists not only the exit-points, but relays as well. Fortunately, his list is automated, but I had to shut down the TOR node.
Barraccuda removes by request, however, sells “subscription” for $20, so you will not be in the list again. That’s low!
At the moment it’s in the APEWS for 3(!) years and the owner has a long faq where he is explaining why he would not remove you ever.
Thinking of extra VPS for the additional MX.
Just for the record: Leaseweb does not support PTR record setting for the IPv6 address from the web panel, but you can ask the support team to set it with ticket. Google rejects my mail that comes from the IPv6 network with “PTR not found” message.