UpLead is a business and enterprise application that provides users with a powerful and easy-to-use lead generation platform. It helps users to search, filter, and connect with potential customers worldwide. With UpLead, users can create custom searches to find leads by industry, geography, company size, title, and more. UpLead offers a wide range of data sources and can even collect data from multiple sources. It also provides a variety of options for managing, segmenting, and nurturing leads, as well as tracking them from acquisition to conversion. UpLead helps businesses to find and engage with the right prospects, increase lead quality and conversion rate, and create better customer experiences.
FullContact
Gardener.gg
Clearbit Connect
Lead411 Community
Gardener is much cheaper than UpLeads. And I think their database also has more emails.