How do you scrap emails in bulk for free?

Hi guys!

Recently I launched Post BrAIner, a tool where you can create articles in seconds and rank high on Google.

I have been following some marketing strategies and now I want to do outbound, because I read it is very effective in B2B models. My target audience are SEO and marketing agencies who may use this tool for their clients to save time and money, but also small businesses who do SEO by themselves.

I see many paying tools where you can get listings of emails, but these are expensive, and I imagine they will offer the same listings to everyone, so I prefer doing it from a different way.

Any of you know how to scrap emails in bulk for free? Which tools do you use for that?

Thank you guys!