How to build email list for my SASS

I have some tips that may be of use to you. Since you are in the pre-launch stage, I'd suggest you, first of all, get yourself listed on as many SaaS listing and review platforms as possible, and your social media such as Facebook, Instagram, and most importantly LinkedIn along with a Wikipedia page should be up and running. Once you created all of this, you can start with the main thing because people will search about you after that and all this is to make sure they know you're a legitimate company.

The "main thing" I referred to here was cold outreach. Cold emailing is really not given as much credit as it should get. In order to build email lists, you can use a prospecting tool like Aeroleads to find potential clients in the niche you're addressing with your product, and to execute the campaigns, automating the emails with an email sequencing tool like MailChimp to automate the email outreach process, just make sure that your email content is valuable and form a good lead nurturing strategy. My suggestion would be to target people in the age group of 20-35 (if your product concerns this group at all) because this segment is what marketers call something like 'the daredevils' while doing market segmentation because they are not afraid/reluctant to test out new products.

Once start sending thousands of emails every few days, people will automatically start searching for you and your product will be quickly caught on by the market.
All the very best!

Does your product give people SASS! I think write blogs that people want to read ad provide a sign up box. Maybe use SubStack?

Content marketing and give away something. Easy-peasy, but it takes a long time of consistent content creation (i.e. blog) to start getting results.

Or, do paid ads that go to an opt-in (Free report or something).