SeaTools is not available for Mac but there are some alternatives that runs on macOS with similar functionality. The best Mac alternative is GSmartControl, which is both free and Open Source. If that doesn't suit you, our users have ranked more than 25 alternatives to SeaTools and five of them are available for Mac so hopefully you can find a suitable replacement. Other interesting Mac alternatives to SeaTools are smartmontools (Free, Open Source), DriveDx (Paid), SMART Utility (Paid) and SMARTReporter (Paid).
The smartmontools package contains two utility programs (smartctl and smartd) to control and monitor storage systems using the Self-Monitoring, Analysis and Reporting Technology System (SMART) built into most modern ATA and SCSI harddisks.
SMARTReporter is an application that can warn you of some hard disk drive failures before they actually happen! It does so by periodically polling the built-in S.M.A.R.T. status of your hard disk drives as well as performing other checks for "I/O errors" or R.A.I.