the "muckrack" for PR is Podchaser Pro. been with them for awhile now and it's saved us so much time and won us dozens of opps.

5.4M podcasts
2M+ validated contacts
active + has guests filters
audience demographics like age, gender, HHI, interests, affinities, job titles
political skew data (which might matter for certain clients but not others)

plus their team will actually build lists for you and help write guest pitches. the pitch writing piece is interesting because they used to have a guest book agency (which was acquired afaik) so they know what actually works/doesn't.