imapsync - Console-based utility for migrating IMAP mailboxes.
Cloudingo - Cloudingo - a cloud-based SaaS, connects to Salesforce and allows system administrators to scan their entire database for similar or duplicate records.
audriga Email and Groupware migration - Easily migrate your email, contacts, calendar items and tasks to your new provider or server. No software installation is required.
CRMfusion - CRMfusion is a suite of data quality and data integration tools that integrate well with Salesforce.
MailStore - MailStore Home - A 100% free single-private-user desktop solution
ZaapIT - Mass Merge, auto merge, duplicates cleanup, bulk edit, bulk update, bulk delete , mass lead convert