Clay

Spreadsheet meets a dozen data providers. Steep learning curve, and the best outbound lists I've seen come out of it.

If Clay isn't right

Apollo.io in sales & outreach
Lead database plus sequences in one tool; best value for prospecting.
Free tier; paid plans available
Instantly in sales & outreach
Cold email at volume with warm-up built in.
Paid; see site
Gong in sales & outreach
Records and scores sales calls. Only pays off once you have several reps and a lot of calls.
Enterprise pricing
lemlist in sales & outreach
Multichannel sequences with personalised images and LinkedIn steps.
Paid; see site