There are free tools for finding direct dials but the hit 4are us pretty mediocre - 40 to 60% on average depending on sector.

HQ # are easy to find although navigating phone trees and gatekeepers is a job unto itself

Zoominfo and a few others are super expensive but have better data.

Google works better than you think. Sales navigator has some numbers.

We usually call when an email has been opened multiple times and get really good hit rates for demos when we actually reach the person (when talking about SAAS). Last week one of my guys used that to book demos with Disney, Sony, and NBC Universal at the VP level to demo enterprise marketing software.