There might be some services here to try out: https://docs.google.com/spreadsheets/d/1hif4buUftI8FYD2r5g6rEw3UvWl4zwt5Ep44QI2RksY/edit#gid=16
Also look at:
- violanorbert.com 
- Interseller 
- Lush 
- getemail.io. It's a chrome extension 
- Used to use Hunter.io before linkedin shut-off their chrome extension support 
- LeadIQ (an Alchemist company) 
- Groove (an Alchemist company) 
- growbots 
- apollo.io for prospecting, automating outbound - its great! and it integrates with salesforce which is super helpful 
