SniperPhish is an all-in-one open-source phishing toolkit that pentesters and other security professionals can use for setting up and executing email and web-based spear phishing campaigns. The tool can create and schedule phishing email campaigns, create web and email tracker code, create custom tracker images, combine phishing sites with email campaigns for central tracking, track replies to phishing messages, generate reports, and more. It also provides a variety of customization options for sending emails (such as mail delay, anti-flood control, etc.)
Source: https://www.helpnetsecurity.com/2021/04/26/sniperphish-phishing-toolkit/