It'd be easier to reply to this question if we knew why and from what you're trying to extract emails.
With that being said, if you're looking to build an email list, you can use tools & platforms such as:
- LinkedIn Sales Navigator
- Crunchbase
- Builtwith
to have data to work with. Then use tools such as Phantombuster and TexAu to extract data. Finally tools such as:
- ColdCRM
- Snov
- Anymailfinder
to gather email addresses.
Hope this helps even though the question might not be about that at all haha