ProntoEngage
ProntoEngage sections
ProntoEngage is a bulk Lead to Campaign import tool. ProntoEngage will check whether the Lead/Contact already exists in Salesforce based on certain criteria, and if not, create a new Lead and add it to a campaign.
Why should I use ProntoEngage to import my data as opposed to native Salesforce Data Loader and Data Importer, you might ask.
Native tools will not check for duplicates across BOTH Leads and Contacts, meaning if you have an existing Contact in Salesforce with an email address, and you have the same email address on a new List to be imported to a Campaign, you would probably import them as a new Lead in Salesforce, then obtain the LeadID to then import them as a Campaign Member under your Campaign (referencing the correct CampaignID).
ProntoEngage offers a simple User Interface to remove that hassle of multiple steps for you.