Best Tools and Strategies for Email Validation to Reduce Bounce Rates on Cold Outbound Lists

Hey everyone -- what are people using for email validation on cold outbound lists right now? Use case

Running ZeroBounce as the primary pass in Clay but it’s not catching enough -- seeing 5-7% bounce rates on already-validated lists. Accept-all domains seem to be the main culprit. Added BounceBan as a second pass via HTTP API in Clay. Ran it today on a 483-lead list -- caught 62 additional bad addresses ZeroBounce passed. Threshold that worked: result = deliverable AND (accept_all = false OR score >= 95). That accept-all carve-out made a big difference. Client has 90K credits so I have runway to keep testing, but ideally want something more permanent.

Anyone using something with native Clay integration that handles accept-all reliably?