Some Useful Tools Are Listed Below

ActiveCampaign – best for small businesses & enterprise

Benchmark – best for agencies 

Brevo – best for transactional emails

Drip – best for small-medium eCommerce businesses

Omnisend – best for medium-large eCommerce businesses

Autopilot – best for marketing automation

Hubspot – best for B2B service companies

MailerLite – best for personal projects

ConvertKit – best for bloggers

EmailOctopus – best for developers (uses AWS)

Campaign Monitor – Great for Agencies