I know there is a domain pool zone file but that is beyond my scope's ability. So does anybody know a good tool or a method to achieve this thing? I feel this is possible because I noticed when one start a new website with wordpress, those spam bots somehow immediately send you spams within hours, so I guess there should be some ways? Any ideas?
... for free. There are tons of companies offering this service, but you gotta pony up some dough. Also this sounds like you're trying to set up a service that bothers people with those emails like "You've just registered extension .com, but extension .xyz is also available" and I hate that. Can you justify your needs for this?
Here [1] is some discussion on stackexchange and here [2] is a script that apparently scrapes some data from the free lists on whoisd [3]. I'm finding a rather large number of businesses built around this data.
[1] - https://webmasters.stackexchange.com/questions/121160/how-to...
[2] - https://github.com/gfek/Hunting-New-Registered-Domains