For cold emails, you can use tools like Instantly, SmartReach, PlusVibe, or Manyreach. These are made for reaching out to people who have not signed up yet.
For emails to people who already joined your list, you should use tools like Brevo, MailerLite, Mailchimp, or MailerSpark. These are better for regular updates, offers, and newsletters.
When it comes to cold emails, keep the volume low. Do not send too many emails at once. Also, avoid sending the same message to everyone by just changing the name. That approach does not work anymore.
Even if you use the best tools, your emails can still go to spam. AI has become very smart now, and it can detect spam messages within seconds. So you need to make your emails more natural and personal.